diff --git a/.buildkite/Manifest.toml b/.buildkite/Manifest.toml
index f00140bf443..acd64b6ea8f 100644
--- a/.buildkite/Manifest.toml
+++ b/.buildkite/Manifest.toml
@@ -1,6 +1,6 @@
 # This file is machine-generated - editing it directly is not advised
 
-julia_version = "1.12.4"
+julia_version = "1.12.5"
 manifest_format = "2.0"
 project_hash = "5023fc07bb1b56800f97a2d66fbd8bd8c9c8d7a1"
 
@@ -116,9 +116,9 @@ version = "1.12.1"
 
 [[deps.Preferences]]
 deps = ["TOML"]
-git-tree-sha1 = "522f093a29b31a93e34eaea17ba055d850edea28"
+git-tree-sha1 = "8b770b60760d4451834fe79dd483e318eee709c4"
 uuid = "21216c6a-2e73-6563-6e65-726566657250"
-version = "1.5.1"
+version = "1.5.2"
 
 [[deps.Printf]]
 deps = ["Unicode"]
diff --git a/.buildkite/build.sh b/.buildkite/build.sh
index f813d0f62a1..6e5719ae0ee 100755
--- a/.buildkite/build.sh
+++ b/.buildkite/build.sh
@@ -2,12 +2,22 @@
 # Fail on error
 set -e
 
+SCRIPT_DIR="$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
+YGGDRASIL_BASE="$(dirname "${SCRIPT_DIR}")"
+JULIA_PROJECT="${YGGDRASIL_BASE}/${JULIA_PROJECT:-/foo}"
+
+# Early-exit if someone is blindly running this manually
+if [[ ! -d "${JULIA_PROJECT:-}" ]]; then
+    echo "ERROR: Must set JULIA_PROJECT to one of:" >&2
+    echo "  - ${YGGDRASIL_BASE}/.ci/bb1_project" >&2
+    echo "  - ${YGGDRASIL_BASE}/.ci/bb2_project" >&2
+    exit 1
+fi
+
 # Clear secrets from environment
 export BUILDKITE_PLUGIN_CRYPTIC_BASE64_SIGNED_JOB_ID_SECRET=""
 export AWS_SECRET_ACCESS_KEY=""
 
-export JULIA_PROJECT="${BUILDKITE_BUILD_CHECKOUT_PATH}/.ci"
-
 # Add our shared depot cache to the end of JULIA_DEPOT_PATH which is already
 # filled out by `julia-buildkite-plugin` to our agent/pipeline-specific depot path.
 # Make sure to append a colon at the end to allow use of shipped stdlib caches.
@@ -17,17 +27,15 @@ echo "--- Set JULIA_DEPOT_PATH to ${JULIA_DEPOT_PATH}"
 echo "--- Setup Julia packages"
 julia --color=yes -e 'import Pkg; Pkg.instantiate(); Pkg.precompile()'
 
-# Cleanup temporary things that might have been left-over
-echo "--- Cleanup"
-./clean_builds.sh
-./clean_products.sh
-
-echo "+++ Build"
-cd "${PROJECT}"
-
 # Parallel auditor can end up opening loads of files and causing
 # "Too many open files" errors.  Increase the limit.
 ulimit -n 65536
 
-# Start Julia with multiple thread to make auditor parallel.
-julia --threads "${BINARYBUILDER_NPROC:-16}" ./build_tarballs.jl --verbose "${PLATFORM}"
+# Cleanup temporary things that might have been left-over
+echo "--- Cleanup"
+"${YGGDRASIL_BASE}/clean_builds.sh"
+"${YGGDRASIL_BASE}/clean_products.sh"
+
+echo "+++ Build"
+# Start Julia with multiple threads to make auditor parallel.
+julia --threads "${BINARYBUILDER_NPROC:-16}" ./build_tarballs.jl --verbose "$@"
diff --git a/.buildkite/generator.jl b/.buildkite/generator.jl
index 230ce77aec3..6dd5e271117 100755
--- a/.buildkite/generator.jl
+++ b/.buildkite/generator.jl
@@ -1,8 +1,25 @@
 #!/bin/env julia
-if VERSION < v"1.8.0"
-    Base.ACTIVE_PROJECT[] = @__DIR__
+import Pkg
+
+Base.set_active_project(@__DIR__)
+using YAML
+
+const PROJECTS = copy(ARGS)
+const DEBUG = !haskey(ENV, "BUILDKITE")
+const IS_PR = get(ENV, "BUILDKITE_PULL_REQUEST", "false") != "false"
+const SKIP_BUILD_COOKIE="[skip build]"
+
+if IS_PR
+    # If we're on a PR though, we look at the entire branch at once
+    BASE_BRANCH = get(ENV, "BUILDKITE_PULL_REQUEST_BASE_BRANCH", "master")
+    @assert !isempty(BASE_BRANCH)
+
+    PR_NUMBER = ENV["BUILDKITE_PULL_REQUEST"]
+    run(ignorestatus(`git fetch origin "refs/pull/$(PR_NUMBER)/head:refs/remotes/origin/pr/$(PR_NUMBER)"`))
+
+    COMMIT_MSG = readchomp(`git show -s --format=%B origin/pr/$(PR_NUMBER)`)
 else
-    Base.set_active_project(@__DIR__)
+    COMMIT_MSG = readchomp(`git show -s --format=%B`)
 end
 
 # Force ourselves to use the shared depot as well, if it exists
@@ -10,125 +27,155 @@ if isdir("/sharedcache/depot")
     push!(Base.DEPOT_PATH, "/sharedcache/depot")
 end
 
-import Pkg
+# Instantiate, to install all necessary packages like YAML (not BinaryBuilder)
 Pkg.instantiate()
 
-using Downloads, Dates, SHA
+include("utils.jl")
 
-const PROJECT = only(ARGS)
-const DEBUG = !haskey(ENV, "BUILDKITE")
+# Give a warning if the pkgserver is too far behind
+check_pkgserver_latency()
 
-include("utils.jl")
+# If there are scary projects we need to exclude, we list them here. (Used to contain `LLVM`)
+EXCLUDED_NAMES = Set{String}([])
 
-if !isnothing(Pkg.pkg_server())
-    resp = try
-        headers = Pkg.PlatformEngines.get_metadata_headers(Pkg.pkg_server())
-        Downloads.request("$(Pkg.pkg_server())/registries"; headers)
-    catch e
-        # Let us know the download of the registry went wrong, but do not hard fail
-        @error "Could not download the registry" exception=(e, catch_backtrace())
-    end
-    last_mod_idx = findfirst(h -> first(h) == "last-modified", resp.headers)
-    msg = "PkgServer: " * resp.url
-    delay = if !isnothing(last_mod_idx)
-        last_mod = last(resp.headers[last_mod_idx])
-        msg *= " -- last updated: " * last_mod
-        # Manually strip the "GMT" timezone and hope it never changes.
-        # Do not error out if parsing fails.
-        dt = tryparse(DateTime, replace(last_mod, " GMT"=>""), dateformat"e, d u y H:M:S")
-        # If parsing did fail, set the delay to 0.
-        isnothing(dt) ? Second(0) : now(UTC) - dt
-    else
-        Second(0)
-    end
-    delay > Second(0) && (msg *= " (" * string(Dates.canonicalize(round(delay, Second))) * " ago)")
-    @info(msg)
-    annotate(msg, style="info", context="pkg")
-    tolerance = Hour(1)
-    if delay > tolerance
-        @warn "The PkgServer registry is older than $(tolerance)"
-        annotate("The PkgServer registry is older than $(tolerance)", style = "warning", context="pkg")
+filter!(PROJECTS) do project
+    if project ∈ EXCLUDED_NAMES
+        @info("Skipping project since it is excluded.", project)
+        return false
     end
+    return true
 end
 
-# If there are scary projects we need to exclude, we list them here. (Used to contain `LLVM`)
-EXCLUDED_NAMES = Set{String}([])
+# Clear out any old `.meta.json` files in the Yggdrasil root
+cleanup_metadata!()
 
-if PROJECT ∈ EXCLUDED_NAMES
-    @info "Skipping project since it is excluded." PROJECT
-    exit()
+# Immediately read in all projects, and ensure that they are either all BB2 projects, or none of them are:
+bb2_projects = String[]
+bb1_projects = String[]
+for project in PROJECTS
+    if uses_bb2(project)
+        push!(bb2_projects, project)
+    else
+        push!(bb1_projects, project)
+    end
 end
 
-# Remove secret from environment
-sanitize(cmd) = addenv(cmd, Dict("BUILDKITE_PLUGIN_CRYPTIC_BASE64_SIGNED_JOB_ID_SECRET" => nothing))
-exec(cmd) = @assert success(pipeline(sanitize(cmd), stderr=stderr, stdout=stdout))
+function bb1_build_steps!(group_steps, project)
+    # determine the name, removing any trailing version number
+    # (`L/LLVM/LLVM@14` results in `NAME = "LLVM"`)
+    project_basename = basename(project)
 
-YGGDRASIL_BASE = dirname(@__DIR__)
-julia(args) = `$(Base.julia_cmd()) --project=$(YGGDRASIL_BASE)/.ci $args`
+    # We always invoke a `build_tarballs.jl` file from its own directory to generate the platform list
+    cd(project) do
+        println("[$(project)] Generating meta.json...")
+        json_path = "$(YGGDRASIL_BASE)/$(project_basename).meta.json"
+        julia(`--compile=min ./build_tarballs.jl --meta-json="$(json_path)"`; julia_project = bb1_julia_project)
 
-# Next, we're going to ensure that our BB is up to date and precompiled
-julia(`-e "import Pkg; Pkg.instantiate(); Pkg.precompile()"`) |> exec
+        # Generate platforms
+        julia(`$(bb1_julia_project)/generate_platforms.jl "$(json_path)" $(YGGDRASIL_BASE)/$(project_basename).platforms.list`)
+    end
 
-TEMP = mktempdir()
+    platforms = split(readchomp(joinpath(YGGDRASIL_BASE, "$(project_basename).platforms.list")))
+    if isempty(platforms)
+        @error("Unable to determine the proper platforms", project_basename)
+        exit(1)
+    end
 
-# determine the name, removing any trailing version number
-# (`L/LLVM/LLVM@14` results in `NAME = "LLVM@14"`)
-const NAME = first(split(basename(PROJECT), "@"))
+    should_skip_builds = contains(COMMIT_MSG, SKIP_BUILD_COOKIE)
+    steps = []
+    for platform in platforms
+        if !should_skip_builds
+            println("[$(project)] $(platform): building")
+            bs = BB1BuildStep(
+                project_basename,
+                project,
+                platform,
+            )
+            push!(steps, render(bs))
+        end
+    end
 
-# We always invoke a `build_tarballs.jl` file from its own directory
-# generate platform list
-cd(PROJECT) do
-    println("Generating meta.json...")
-    JSON_PATH = "$(TEMP)/$(NAME).meta.json"
-    julia(`--compile=min ./build_tarballs.jl --meta-json="$(JSON_PATH)"`) |> exec
+    # If this is not a pull request, we're going to register this project
+    if !IS_PR
+        push!(steps, wait_step())
+        push!(steps, render(BB1RegisterStep(
+            project_basename,
+            project,
+            should_skip_builds,
+            length(platforms),
+        )))
+        #push!(steps, wait_step())
+        #push!(steps, register_step(project_name, project, should_skip_builds, length(platforms)))
+    end
 
-    # Generate platforms
-    julia(`$(YGGDRASIL_BASE)/.ci/generate_platforms.jl "$(JSON_PATH)" $(TEMP)/$(NAME).platforms.list`) |> exec
+    # Group this project's full build under `project_name`
+    if !isempty(steps)
+        push!(group_steps, group_step(project_basename, steps))
+    end
 end
 
-println("Determining builds to queue...")
-
-# Load in the platforms
-PLATFORMS = split(readchomp(joinpath(TEMP, "$(NAME).platforms.list")))
-if isempty(PLATFORMS)
-    @error "Unable to determine the proper platforms" NAME
+function bb2_build_steps!(group_steps, projects)
+    # Invoke `scheduler.jl` to build up our list of jobs with their dependencies
+    io = IOBuffer()
+    julia(`$(bb2_julia_project)/scheduler.jl $(projects)`; julia_project=bb2_julia_project, stdout=io)
+    groups = YAML.load(String(take!(io)))
+
+    # We will create one group per packaging project, and each build will belong to one of those 
+    for (group_name, group) in groups
+        builds = []
+        steps = []
+        for build in group["builds"]
+            bs = BB2BuildStep(
+                build["name"],
+                group_name,
+                build["platform"],
+                build["build_hash"],
+                build["dependencies"],
+            )
+            push!(builds, bs)
+            push!(steps, render(bs))
+        end
+
+        for packaging in group["packagings"]
+            deps = vcat(
+                # Other packages that must be registered
+                packaging["dependencies"],
+                # Our own builds
+                builds,
+            )
+            rs = BB2RegisterStep(packaging["name"], group_name, deps)
+            push!(steps, render(rs))
+        end
+        push!(group_steps, group_step(group_name, steps))
+    end
 end
 
-const IS_PR = get(ENV, "BUILDKITE_PULL_REQUEST", "false") != "false"
-const SKIP_BUILD_COOKIE="[skip build]"
 
-if IS_PR
-    # If we're on a PR though, we look at the entire branch at once
-    BASE_BRANCH = get(ENV, "BUILDKITE_PULL_REQUEST_BASE_BRANCH", "master")
-    @assert !isempty(BASE_BRANCH)
+function build_steps!(group_steps, bb1_projects, bb2_projects)
+    if !isempty(bb1_projects)
+        # Ensure BB1 is instantiated
+        julia(`-e "import Pkg; Pkg.instantiate(); Pkg.precompile()"`; julia_project=bb1_julia_project)
 
-    PR_NUMBER = ENV["BUILDKITE_PULL_REQUEST"]
-    exec(`git fetch origin "refs/pull/$(PR_NUMBER)/head:refs/remotes/origin/pr/$(PR_NUMBER)"`)
+        # Each project is processed individually, with a group of builds for each platform.
+        for project in bb1_projects
+            bb1_build_steps!(group_steps, project)
+        end
+    end
 
-    COMMIT_MSG = readchomp(`git show -s --format=%B origin/pr/$(PR_NUMBER)`)
-else
-    COMMIT_MSG = readchomp(`git show -s --format=%B`)
-end
-# This variable will tell us whether we want to skip the build
-const SKIP_BUILD = contains(COMMIT_MSG, SKIP_BUILD_COOKIE)
+    if !isempty(bb2_projects)
+        # Ensure BB2 is instantiated
+        julia(`-e "import Pkg; Pkg.instantiate(); Pkg.precompile()"`; julia_project=bb2_julia_project)
 
-STEPS = Any[]
-# Create the BUILD_STEPS
-if SKIP_BUILD
-    println("The commit messages contains $(SKIP_BUILD_COOKIE), skipping build")
-else
-    for PLATFORM in PLATFORMS
-        println("    $(PLATFORM): building")
-        push!(STEPS, build_step(NAME, PLATFORM, PROJECT))
+        # For BB2, we jointly process all `build_tarballs.jl` files, building a dependency graph:
+        bb2_build_steps!(group_steps, bb2_projects)
     end
 end
-if !IS_PR
-    push!(STEPS, wait_step())
-    push!(STEPS, register_step(NAME, PROJECT, SKIP_BUILD, length(PLATFORMS)))
-end
-if !isempty(STEPS)
-    definition = Dict(
-        :steps => Any[group_step(NAME, STEPS)]
-    )
-    upload_pipeline(definition)
+
+
+group_steps = []
+build_steps!(group_steps, bb1_projects, bb2_projects)
+
+# Only upload the pipieline if we actually have something to upload
+if !isempty(group_steps)
+    upload_pipeline(Dict(:steps => group_steps))
 end
diff --git a/.buildkite/pipeline.yml b/.buildkite/pipeline.yml
index d70a78b813f..a7d647a4f96 100644
--- a/.buildkite/pipeline.yml
+++ b/.buildkite/pipeline.yml
@@ -3,7 +3,7 @@ steps:
     plugins:
       - JuliaCI/julia#v1:
           persist_depot_dirs: packages,artifacts,compiled
-          version: "1.12.4"
+          version: "1.12.5"
           artifacts_size_limit: "214748364800" # 200GB
       - JuliaCI/merge-commit: ~
       - staticfloat/forerunner#v1:
@@ -13,6 +13,9 @@ steps:
           path_processor: .buildkite/path_processors/per-project
           target: .buildkite/generator.jl
           target_type: command
+    artifacts:
+      - "*.meta.json"
+      - "*.platforms.list"
     agents:
       queue: "yggdrasil"
       arch:  "x86_64"
diff --git a/.buildkite/pipeline.yml.signature b/.buildkite/pipeline.yml.signature
index f0dce700971..f904dbdd952 100644
Binary files a/.buildkite/pipeline.yml.signature and b/.buildkite/pipeline.yml.signature differ
diff --git a/.buildkite/register.sh b/.buildkite/register.sh
index c65f4192f7e..bed82110d6c 100755
--- a/.buildkite/register.sh
+++ b/.buildkite/register.sh
@@ -2,19 +2,20 @@
 # Fail on error
 set -e
 
-export JULIA_PROJECT="${BUILDKITE_BUILD_CHECKOUT_PATH}/.ci"
+SCRIPT_DIR="$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
+YGGDRASIL_BASE="$(dirname "${SCRIPT_DIR}")"
+JULIA_PROJECT="${YGGDRASIL_BASE}/${JULIA_PROJECT:-/foo}"
+
+# Early-exit if someone is blindly running this manually
+if [[ ! -d "${JULIA_PROJECT:-}" ]]; then
+    echo "ERROR: Must set JULIA_PROJECT to one of:" >&2
+    echo "  - ${YGGDRASIL_BASE}/.ci/bb1_project" >&2
+    echo "  - ${YGGDRASIL_BASE}/.ci/bb2_project" >&2
+    exit 1
+fi
 
 echo "--- Setup Julia packages"
 GITHUB_TOKEN="" julia --color=yes -e 'import Pkg; Pkg.instantiate(); Pkg.precompile()'
 
-cd "${PROJECT}"
-echo "--- Generating meta.json..."
-GITHUB_TOKEN="" julia --compile=min ./build_tarballs.jl --meta-json=${NAME}.meta.json
-
-echo "--- Setting up git"
-git config --global user.name "jlbuild"
-git config --global user.email "juliabuildbot@gmail.com"
-
-echo "--- Registering ${NAME}..."
-julia ${BUILDKITE_BUILD_CHECKOUT_PATH}/.ci/register_package.jl "${NAME}.meta.json" --verbose
-
+echo "--- Registering..."
+julia ${JULIA_PROJECT}/register_package.jl "${META_JSON:-}" --verbose
diff --git a/.buildkite/utils.jl b/.buildkite/utils.jl
index e6f29be85d6..6fe48320cb7 100644
--- a/.buildkite/utils.jl
+++ b/.buildkite/utils.jl
@@ -1,15 +1,61 @@
-import YAML
+import Downloads, Pkg, YAML
+using Dates
+
+function check_pkgserver_latency(; tolerance = Hour(1))
+    # Nothing to do if this is empty
+    if isnothing(Pkg.pkg_server())
+        return
+    end
+
+    resp = try
+        headers = Pkg.PlatformEngines.get_metadata_headers(Pkg.pkg_server())
+        Downloads.request("$(Pkg.pkg_server())/registries"; headers)
+    catch e
+        # Let us know the download of the registry went wrong, but do not hard fail
+        @error "Could not download the registry" exception=(e, catch_backtrace())
+    end
+
+    last_mod_idx = findfirst(h -> first(h) == "last-modified", resp.headers)
+    msg = "PkgServer: " * resp.url
+    delay = if !isnothing(last_mod_idx)
+        last_mod = last(resp.headers[last_mod_idx])
+        msg *= " -- last updated: " * last_mod
+        # Manually strip the "GMT" timezone and hope it never changes.
+        # Do not error out if parsing fails.
+        dt = tryparse(DateTime, replace(last_mod, " GMT"=>""), dateformat"e, d u y H:M:S")
+        # If parsing did fail, set the delay to 0.
+        isnothing(dt) ? Second(0) : now(UTC) - dt
+    else
+        Second(0)
+    end
+    delay > Second(0) && (msg *= " (" * string(Dates.canonicalize(round(delay, Second))) * " ago)")
+    @info(msg)
+    annotate(msg, style="info", context="pkg")
+    if delay > tolerance
+        @warn "The PkgServer registry is older than $(tolerance)"
+        annotate("The PkgServer registry is older than $(tolerance)", style = "warning", context="pkg")
+    end
+end
+
+# Cleanup `.meta.json` or `.platform.list` files from previous BB1 runs
+function cleanup_metadata!()
+    for (root, _, files) in walkdir(YGGDRASIL_BASE)
+        for file in files
+            if endswith(file, ".meta.json") || endswith(file, ".platforms.list")
+                rm(joinpath(root, file))
+            end
+        end
+    end
+end
 
 function upload_pipeline(definition)
     try
         open(`buildkite-agent pipeline upload --no-interpolation`, stdout, write=true) do io
             YAML.write(io, definition)
         end
-    catch
-        println(stderr, "pipeline upload failed:")
-        YAML.write(stderr, definition)
-        println(stderr)
-        rethrow()
+    catch e
+        @error("pipeline upload failed", e)
+        YAML.write(stdout, definition)
     end
 end
 
@@ -17,8 +63,12 @@ function annotate(annotation; context="default", style="info", append=true)
     @assert style in ("success", "info", "warning", "error")
     append = append ? `--append` : ``
     cmd = `buildkite-agent annotate --style $(style) --context $(context) $(append)`
-    open(cmd, stdout, write=true) do io
-        write(io, annotation)
+    try
+        open(cmd, stdout, write=true) do io
+            write(io, annotation)
+        end
+    catch err
+        @error("Unable to annotate", err)
     end
 end
 
@@ -32,33 +82,73 @@ agent() = Dict(
 plugins() = Pair{String, Union{Nothing, Dict}}[
     "JuliaCI/julia#v1" => Dict(
         "persist_depot_dirs" => "packages,artifacts,compiled",
-        "version" => "1.12.4",
+        "version" => "1.12.5",
         "artifacts_size_limit" => string(120 << 30), # 120 GiB
     ),
     "JuliaCI/merge-commit" => nothing
 ]
 
-env(NAME, PROJECT) = Dict(
+
+safe_name(fn::AbstractString) = replace(fn, r"[^A-Za-z0-9_\-:]"=>"-")
+
+wait_step() = Dict(:wait => nothing)
+group_step(name, steps) = Dict(:group => name, :steps => steps)
+
+function init_git_config()
+    git_config_dir = mktempdir()
+    git_config = joinpath(git_config_dir, "config")
+    open(git_config, write=true) do io
+        println(io, "[user]")
+        println(io, "\name = jlbuild")
+        println(io, "\temail = juliabuildbot@gmail.com")
+    end
+    return git_config
+end
+
+env() = Dict(
     "JULIA_PKG_SERVER" => "us-east.pkg.julialang.org",
     "JULIA_PKG_SERVER_REGISTRY_PREFERENCE" => "eager",
     "JULIA_REGISTRYCI_AUTOMERGE" => "true",
-    "NAME" => NAME,
-    "PROJECT" => PROJECT,
     "YGGDRASIL" => "true",
     # Inherit the secret so that we can decrypt cryptic secrets
     "BUILDKITE_PLUGIN_CRYPTIC_BASE64_SIGNED_JOB_ID_SECRET" => get(ENV, "BUILDKITE_PLUGIN_CRYPTIC_BASE64_SIGNED_JOB_ID_SECRET", ""),
+    
+    # Store the (global) git config here, seed it with jlbuild values, and tell git to use only it
+    "GIT_CONFIG_GLOBAL" => init_git_config(),
+    "GIT_CONFIG_NOSYSTEM" => "true",
 )
 
-safe_name(fn::AbstractString) = replace(fn, r"[^A-Za-z0-9_\-:]"=>"-")
+abstract type AbstractStep; end
 
-wait_step() = Dict(:wait => nothing)
-group_step(name, steps) = Dict(:group => name, :steps => steps)
+abstract type AbstractBuildStep <: AbstractStep; end
+struct BB1BuildStep <: AbstractBuildStep
+    name::String
+    project::String
+    platform::String
+end
 
-function build_step(NAME, PLATFORM, PROJECT)
-    script = raw"""
-    .buildkite/build.sh
-    """
+bb1_step_key(project_name::String, platform::String) = "$(safe_name(project_name))--$(safe_name(platform))"
+step_key(bs::BB1BuildStep) = bb1_step_key(bs.project, bs.platform)
 
+struct BB2BuildStep <: AbstractBuildStep
+    name::String
+    project::String
+    platform::String
+    build_hash::String
+    dependencies::Vector{String}
+end
+step_key(bs::BB2BuildStep) = "$(safe_name(bs.project))--$(bs.build_hash[5:13])"
+universe_name(bs::BB2BuildStep) = "$(safe_name(bs.project))-$(YGGDRASIL_COMMIT)"
+
+function universe_flag(s)
+    # If we're on a PR, deploy to a custom universe on a custom org
+    if get(ENV, "BUILDKITE_PULL_REQUEST", "false") != "false"
+        "--universe=$(universe_name(s))"
+    end
+    return ""
+end
+
+function render(bs::AbstractBuildStep)
     build_plugins = plugins()
     push!(build_plugins,
         "staticfloat/cryptic#v2" => Dict(
@@ -66,51 +156,89 @@ function build_step(NAME, PLATFORM, PROJECT)
                 "AWS_SECRET_ACCESS_KEY=\"U2FsdGVkX1846b0BRbZjwIWSFV+Fiv1C/Hds/vB3aTkxubHPnRP6lVxGkAkOcFuvAntkoLF6J64QrOHWvjz8xg==\"",
             ]
         ),
-        "staticfloat/coppermind#v2" => Dict(
-            "inputs" => [
-                PROJECT,
-                ".ci/",
-                # ?meta.json
-            ],
-            "s3_prefix" => "s3://julia-bb-buildcache/"
-        ),
     )
-    build_env = env(NAME, PROJECT)
-    merge!(build_env, Dict(
-        "PLATFORM" => PLATFORM,
+
+    # Only use coppermind on BB1, we're going to do caching with BB2 differently.
+    if isa(bs, BB1BuildStep)
+        push!(build_plugins,
+            "staticfloat/coppermind#v2" => Dict(
+                "inputs" => [
+                    bs.project,
+                    ".ci/",
+                    # ?meta.json
+                ],
+                "s3_prefix" => "s3://julia-bb-buildcache/"
+            ),
+        )
+    end
+
+    # On BB1, we pass the platform to build for, on BB2 we identify by build hash
+    if isa(bs, BB1BuildStep)
+        build_sh_args = "$(bs.platform)"
+    else
+        build_sh_args = "$(universe_flag(bs)) --build-hashes=$(bs.build_hash) --archive-dir=products"
+    end
+
+    build_env = merge(env(), Dict(
+        # These are all BinaryBuilder1 specific, but they don't hurt to send to BB2
         "BINARYBUILDER_AUTOMATIC_APPLE" => "true",
         "BINARYBUILDER_USE_CCACHE" => "true",
         "BINARYBUILDER_STORAGE_DIR" => "/cache/yggdrasil",
         "BINARYBUILDER_CCACHE_DIR" => "/sharedcache/ccache",
         "BINARYBUILDER_NPROC" => "16", # Limit parallelism somewhat to avoid OOM for LLVM
+
+        # This is for coppermind
         "AWS_ACCESS_KEY_ID" => "AKIA4WZGSTHCB2YWWN46",
         "AWS_DEFAULT_REGION" => "us-east-1",
+
+        # Set the julia project to either the BB1 or BB2 project
+        "JULIA_PROJECT" => julia_project(bs),
     ))
 
-    Dict(
-        :key => "$(safe_name(PROJECT))--$(safe_name(PLATFORM))",
-        :label => "build -- $PROJECT -- $PLATFORM",
+    return Dict(
+        :key => step_key(bs),
+        :label => "build -- $(bs.name) -- $(bs.platform)",
         :agents => agent(),
         :plugins => build_plugins,
         :timeout_in_minutes => 240,
         :priority => -1,
         # Reduce concurrency for Reactant builds, which are extremely intensive and grind
         # the system to a halt when run with several parallel jobs.
-        :concurrency => NAME == "Reactant" ? 8 : 12,
-        :concurrency_group => "yggdrasil/build/$NAME", # Could use ENV["BUILDKITE_JOB_ID"]
-        :commands => [script],
+        :concurrency => startswith(bs.name, "Reactant") ? 8 : 12,
+        :concurrency_group => "yggdrasil/build/$(bs.project)",
+        :commands => ["""
+        YGGDRASIL_BASE=\$(pwd)
+        cd $(bs.project)
+        "\${YGGDRASIL_BASE}/.buildkite/build.sh" $(build_sh_args)
+        cd "\${YGGDRASIL_BASE}"
+        """],
         :env => build_env,
         :artifacts => [
-            "**/products/$NAME*.tar.*"
+            "$(bs.project)/products/*"
         ]
     )
 end
 
-function register_step(NAME, PROJECT, SKIP_BUILD, NUM_PLATFORMS)
-    script = raw"""
-    BUILDKITE_PLUGIN_CRYPTIC_BASE64_SIGNED_JOB_ID_SECRET="" .buildkite/register.sh
-    """
+abstract type AbstractRegisterStep <: AbstractStep; end
+struct BB1RegisterStep <: AbstractRegisterStep
+    name::String
+    project::String
+    skip_build::Bool
+    num_platforms::Int
+end
+
+step_key(rs::BB1RegisterStep) = "register-$(rs.name)"
+
+struct BB2RegisterStep <: AbstractRegisterStep
+    name::String
+    project::String
+
+    dependencies::Vector{AbstractStep}
+end
+step_key(rs::BB2RegisterStep) = "register-$(rs.name)"
+universe_name(rs::BB2RegisterStep) = "$(safe_name(rs.project))-$(YGGDRASIL_COMMIT)"
 
+function render(rs::AbstractRegisterStep)
     register_plugins = plugins()
     push!(register_plugins,
         "staticfloat/cryptic#v2" => Dict(
@@ -119,27 +247,78 @@ function register_step(NAME, PROJECT, SKIP_BUILD, NUM_PLATFORMS)
             ]
 	  ))
 
-    register_env = env(NAME, PROJECT)
-    if SKIP_BUILD
-        register_env["SKIP_BUILD"] = "true"
+    register_env = env()
+    register_env["JULIA_PROJECT"] = julia_project(rs)
+    if isa(rs, BB1RegisterStep)
+        if rs.skip_build
+            register_env["SKIP_BUILD"] = "true"
+        end
+        register_env["META_JSON"] = joinpath(YGGDRASIL_BASE, "$(rs.name).meta.json")
+
+        # For packages with a large number of platforms, trying to upload several release
+        # artifacts at once with `ghr` results in exceeding GitHub's API secondary rate limits.
+        # Ref: <https://github.com/JuliaPackaging/BinaryBuilder.jl/pull/1334>.
+        if rs.num_platforms > 80
+            concurrency = 4
+            @info "Reducing ghr concurrency" NAME NUM_PLATFORMS concurrency
+            register_env["BINARYBUILDER_GHR_CONCURRENCY"] = string(concurrency)
+        end
     end
-    # For packages with a large number of platforms, trying to upload several release
-    # artifacts at once with `ghr` results in exceeding GitHub's API secondary rate limits.
-    # Ref: <https://github.com/JuliaPackaging/BinaryBuilder.jl/pull/1334>.
-    if NUM_PLATFORMS > 80
-        concurrency = 4
-        @info "Reducing ghr concurrency" NAME NUM_PLATFORMS concurrency
-        register_env["BINARYBUILDER_GHR_CONCURRENCY"] = string(concurrency)
+    
+    artifact_download = ""
+    if isa(rs, BB2RegisterStep)
+        artifact_download = "mkdir -p products; buildkite-agent artifact download '$(rs.project)/products/*' 'products'"
     end
 
-    Dict(
-        :label => "register -- $NAME",
+    out = Dict(
+        :key => step_key(rs),
+        :label => "register -- $(rs.name)",
         :agents => agent(),
         :plugins => register_plugins,
         :timeout_in_minutes => 90,
         :concurrency => 1,
         :concurrency_group => "yggdrasil/register",
-        :commands => [script],
-	:env => register_env
+        :commands => ["""
+        set -u BUILDKITE_PLUGIN_CRYPTIC_BASE64_SIGNED_JOB_ID_SECRET
+        YGGDRASIL_BASE=\$(pwd)
+        cd $(rs.project)
+        $(artifact_download)
+        "\${YGGDRASIL_BASE}/.buildkite/register.sh"
+        cd "\${YGGDRASIL_BASE}"
+        """],
+	    :env => register_env,
     )
+
+    if isa(rs, BB2RegisterStep)
+        out[:depends_on] = step_key.(rs.dependencies)
+    end
+
+    return out
+end
+
+# Remove secret from environment
+sanitize(cmd) = addenv(cmd, Dict("BUILDKITE_PLUGIN_CRYPTIC_BASE64_SIGNED_JOB_ID_SECRET" => nothing))
+exec(cmd; stdout=Base.stdout, stderr=Base.stderr) = @assert success(pipeline(sanitize(cmd); stderr, stdout))
+
+YGGDRASIL_BASE = dirname(@__DIR__)
+YGGDRASIL_COMMIT = get(ENV, "BUILDKITE_COMMIT", "1a2b3c")[1:6]
+bb1_julia_project = joinpath(YGGDRASIL_BASE, ".ci/bb1_project")
+bb2_julia_project = joinpath(YGGDRASIL_BASE, ".ci/bb2_project")
+function julia(args; julia_project=bb1_julia_project, stdout = Base.stdout, stderr = Base.stderr)
+    return exec(`$(Base.julia_cmd()) --project=$(julia_project) $args`; stdout, stderr)
+end
+
+function julia_project(s)
+    if isa(s, BB1BuildStep) || isa(s, BB1RegisterStep)
+        return ".ci/bb1_project"
+    else
+        return ".ci/bb2_project"
+    end
+end
+
+# We will use the BinaryBuilder2 environment if there is a `using BinaryBuilder2` in the build_tarballs.jl file
+function uses_bb2(project)
+    build_tarballs_path = joinpath(YGGDRASIL_BASE, project, "build_tarballs.jl")
+    build_tarballs_contents = String(read(open(build_tarballs_path)))
+    return any(startswith.(split(build_tarballs_contents, "\n"), ("using BinaryBuilder2",)))
 end
diff --git a/.ci/Manifest.toml b/.ci/bb1_project/Manifest.toml
similarity index 100%
rename from .ci/Manifest.toml
rename to .ci/bb1_project/Manifest.toml
diff --git a/.ci/Project.toml b/.ci/bb1_project/Project.toml
similarity index 100%
rename from .ci/Project.toml
rename to .ci/bb1_project/Project.toml
diff --git a/.ci/download_sources.jl b/.ci/bb1_project/download_sources.jl
similarity index 100%
rename from .ci/download_sources.jl
rename to .ci/bb1_project/download_sources.jl
diff --git a/.ci/generate_platforms.jl b/.ci/bb1_project/generate_platforms.jl
similarity index 100%
rename from .ci/generate_platforms.jl
rename to .ci/bb1_project/generate_platforms.jl
diff --git a/.ci/register_package.jl b/.ci/bb1_project/register_package.jl
similarity index 100%
rename from .ci/register_package.jl
rename to .ci/bb1_project/register_package.jl
diff --git a/.ci/update_manifest.jl b/.ci/bb1_project/update_manifest.jl
similarity index 100%
rename from .ci/update_manifest.jl
rename to .ci/bb1_project/update_manifest.jl
diff --git a/.ci/bb2_project/Manifest.toml b/.ci/bb2_project/Manifest.toml
new file mode 100644
index 00000000000..58f11556bae
--- /dev/null
+++ b/.ci/bb2_project/Manifest.toml
@@ -0,0 +1,511 @@
+# This file is machine-generated - editing it directly is not advised
+
+julia_version = "1.12.5"
+manifest_format = "2.0"
+project_hash = "f43ce102636991893b567e0ead79cd7d961942b7"
+
+[[deps.ArgTools]]
+uuid = "0dad84c5-d112-42e6-8d28-ef12dabb789f"
+version = "1.1.2"
+
+[[deps.Artifacts]]
+uuid = "56f22d72-fd6d-98f1-02f0-08ddc0907c33"
+version = "1.11.0"
+
+[[deps.Attr_jll]]
+deps = ["Artifacts", "JLLWrappers", "Libdl"]
+git-tree-sha1 = "b8747cda97b6cedbd8dc9fc6218e1d53ce8de32f"
+uuid = "1fd713ca-387f-5abc-8002-d8b8b1623b73"
+version = "2.5.3+0"
+
+[[deps.Base64]]
+uuid = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
+version = "1.11.0"
+
+[[deps.BinaryBuilder2]]
+deps = ["Artifacts", "BinaryBuilderAuditor", "BinaryBuilderGitUtils", "BinaryBuilderPlatformExtensions", "BinaryBuilderProducts", "BinaryBuilderSources", "BinaryBuilderToolchains", "Ccache_jll", "Dates", "Downloads", "Git", "HistoricalStdlibVersions", "Infiltrator", "JLLGenerator", "JLLPrefixes", "KeywordArgumentExtraction", "LazyJLLWrappers", "Libdl", "LocalRegistry", "Logging", "LoggingExtras", "MultiHashParsing", "ObjectFile", "OrderedCollections", "OutputCollectors", "Pkg", "PrecompileTools", "Preferences", "Random", "Reexport", "RegistryTools", "SHA", "Sandbox", "Scratch", "ScratchSpaceGarbageCollector", "StructEquality", "StyledStrings", "TOML", "Test", "TimerOutputs", "TreeArchival", "UserNSSandbox_jll", "gh_cli_jll"]
+git-tree-sha1 = "98005986ee38c5913246f9a6fa42c89b5ef1cd60"
+repo-rev = "main"
+repo-url = "https://github.com/JuliaPackaging/BinaryBuilder2.jl.git"
+uuid = "12aac903-9f7c-5d81-afc2-d9565ea332af"
+version = "1.0.1"
+
+[[deps.BinaryBuilderAuditor]]
+deps = ["BinaryBuilderPlatformExtensions", "BinaryBuilderProducts", "BinaryBuilderSources", "BinaryBuilderToolchains", "JLLGenerator", "ObjectFile", "Pkg", "StyledStrings"]
+git-tree-sha1 = "4d9cc98c984347619a2ec1640016e1875c68806c"
+uuid = "53524979-5234-6e31-4220-6120654b694c"
+version = "0.2.0"
+
+[[deps.BinaryBuilderGitUtils]]
+deps = ["Git", "Git_jll", "MultiHashParsing", "gh_cli_jll"]
+git-tree-sha1 = "14d6018f14d9df6cf92e90e97a98b3027ab4244f"
+uuid = "654d7472-7548-7361-4832-74694762694c"
+version = "0.2.0"
+
+[[deps.BinaryBuilderPlatformExtensions]]
+deps = ["OrderedCollections", "PrecompileTools", "Reexport"]
+git-tree-sha1 = "067afea6e559ffd71dca3125cdbe665635c6a85c"
+uuid = "213f2928-4d72-6f46-7461-4c705f634367"
+version = "0.2.0"
+
+[[deps.BinaryBuilderProducts]]
+deps = ["BinaryBuilderSources", "JLLGenerator", "KeywordArgumentExtraction", "Libdl"]
+git-tree-sha1 = "d1145b66a8a9ed1a9972f4051637b94230189a62"
+uuid = "21737265-7a69-6e4f-4974-6375646f7270"
+version = "0.2.0"
+
+[[deps.BinaryBuilderSources]]
+deps = ["BinaryBuilderGitUtils", "Dates", "Downloads", "Git", "JLLPrefixes", "MultiHashParsing", "Pkg", "Random", "SHA", "Scratch", "TOML", "TimerOutputs", "TreeArchival"]
+git-tree-sha1 = "602033da2f110123543db1ac45861bded509df0c"
+uuid = "316c416d-4527-6863-7465-466137743047"
+version = "0.2.0"
+
+[[deps.BinaryBuilderToolchains]]
+deps = ["Artifacts", "BinaryBuilderPlatformExtensions", "BinaryBuilderSources", "HistoricalStdlibVersions", "JLLPrefixes", "LazyJLLWrappers", "NetworkOptions", "Pkg", "PrecompileTools", "Reexport", "SHA", "Scratch", "TreeArchival"]
+git-tree-sha1 = "a9e66df160930be64aa67d6dea0a5be6ad05c3f3"
+uuid = "33566f4c-336c-3150-6d30-4374274e6143"
+version = "0.3.0"
+
+[[deps.Ccache_jll]]
+deps = ["Artifacts", "CompilerSupportLibraries_jll", "JLLWrappers", "Libdl", "Zlib_jll", "Zstd_jll"]
+git-tree-sha1 = "ff8d49ca66b9731888e3a7dcdda74b5342a5a6fc"
+uuid = "c6bc53e4-e6d8-51d9-af6d-d7969aa08f60"
+version = "4.9.1+0"
+
+[[deps.Compat]]
+deps = ["TOML", "UUIDs"]
+git-tree-sha1 = "9d8a54ce4b17aa5bdce0ea5c34bc5e7c340d16ad"
+uuid = "34da2185-b29b-5c13-b0c7-acf172513d20"
+version = "4.18.1"
+
+    [deps.Compat.extensions]
+    CompatLinearAlgebraExt = "LinearAlgebra"
+
+    [deps.Compat.weakdeps]
+    Dates = "ade2ca70-3891-5945-98fb-dc099432e06a"
+    LinearAlgebra = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+
+[[deps.CompilerSupportLibraries_jll]]
+deps = ["Artifacts", "Libdl"]
+uuid = "e66e0078-7015-5450-92f7-15fbd957f2ae"
+version = "1.3.0+1"
+
+[[deps.Dates]]
+deps = ["Printf"]
+uuid = "ade2ca70-3891-5945-98fb-dc099432e06a"
+version = "1.11.0"
+
+[[deps.Downloads]]
+deps = ["ArgTools", "FileWatching", "LibCURL", "NetworkOptions"]
+uuid = "f43a241f-c20a-4ad4-852c-f6b1247861c6"
+version = "1.7.0"
+
+[[deps.EnumX]]
+git-tree-sha1 = "c49898e8438c828577f04b92fc9368c388ac783c"
+uuid = "4e289a0a-7415-4d19-859d-a7e5c4648b56"
+version = "1.0.7"
+
+[[deps.Expat_jll]]
+deps = ["Artifacts", "JLLWrappers", "Libdl"]
+git-tree-sha1 = "9cb7fe11da6adb8683cbacf8aa9b5237941e3a75"
+uuid = "2e619515-83b5-522b-bb60-26c02a35a201"
+version = "2.7.5+0"
+
+[[deps.ExprTools]]
+git-tree-sha1 = "27415f162e6028e81c72b82ef756bf321213b6ec"
+uuid = "e2ba6199-217a-4e67-a87a-7c52f15ade04"
+version = "0.1.10"
+
+[[deps.FileWatching]]
+uuid = "7b1f6079-737a-58dc-b8bc-7a2ca5c1b5ee"
+version = "1.11.0"
+
+[[deps.Git]]
+deps = ["Git_LFS_jll", "Git_jll", "JLLWrappers", "OpenSSH_jll"]
+git-tree-sha1 = "824a1890086880696fc908fe12a17bcf61738bd8"
+uuid = "d7ba0133-e1db-5d97-8f8c-041e4b3a1eb2"
+version = "1.5.0"
+
+[[deps.Git_LFS_jll]]
+deps = ["Artifacts", "JLLWrappers", "Libdl"]
+git-tree-sha1 = "bb8471f313ed941f299aa53d32a94ab3bee08844"
+uuid = "020c3dae-16b3-5ae5-87b3-4cb189e250b2"
+version = "3.7.0+0"
+
+[[deps.Git_jll]]
+deps = ["Artifacts", "Expat_jll", "JLLWrappers", "LibCURL_jll", "Libdl", "Libiconv_jll", "OpenSSL_jll", "PCRE2_jll", "Zlib_jll"]
+git-tree-sha1 = "0dd4cfb426924210c8f42742751cbde74b27bfa3"
+uuid = "f8c6e375-362e-5223-8a59-34ff63f689eb"
+version = "2.54.0+0"
+
+[[deps.HistoricalStdlibVersions]]
+deps = ["Pkg", "PrecompileTools"]
+git-tree-sha1 = "abdd6437ede003ee3c412b7da655a8dde356a573"
+uuid = "6df8b67a-e8a0-4029-b4b7-ac196fe72102"
+version = "2.0.6"
+
+[[deps.Infiltrator]]
+deps = ["InteractiveUtils", "Markdown", "REPL", "UUIDs"]
+git-tree-sha1 = "b1eccca4ebc42ac306496c5a5677e50251a19ab1"
+uuid = "5903a43b-9cc3-4c30-8d17-598619ec4e9b"
+version = "1.9.10"
+
+[[deps.InteractiveUtils]]
+deps = ["Markdown"]
+uuid = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
+version = "1.11.0"
+
+[[deps.JLLGenerator]]
+deps = ["BinaryBuilderPlatformExtensions", "Dates", "Libdl", "LicenseCheck", "MultiHashParsing", "Pkg", "Reexport", "SHA", "StructEquality", "TOML"]
+git-tree-sha1 = "3f8d48349031d53fb0f19cd84074dcd37f07a809"
+uuid = "73536572-7074-4e69-5270-206c4c6a2061"
+version = "0.4.1"
+weakdeps = ["BinaryBuilderSources"]
+
+    [deps.JLLGenerator.extensions]
+    BinaryBuilderSourcesExt = "BinaryBuilderSources"
+
+[[deps.JLLPrefixes]]
+deps = ["Artifacts", "Git", "HistoricalStdlibVersions", "Pkg", "Preferences", "SHA", "Scratch"]
+git-tree-sha1 = "a5bb3dd3e86ad7fdd07820ffea7bba4e06c133f8"
+uuid = "afc68a34-7891-4c5a-9da1-1c62935e7b0d"
+version = "0.4.2"
+
+[[deps.JLLWrappers]]
+deps = ["Artifacts", "Preferences"]
+git-tree-sha1 = "0533e564aae234aff59ab625543145446d8b6ec2"
+uuid = "692b3bcd-3c85-4b1f-b108-f13ce0eb3210"
+version = "1.7.1"
+
+[[deps.JuliaSyntaxHighlighting]]
+deps = ["StyledStrings"]
+uuid = "ac6e5ff7-fb65-4e79-a425-ec3bc9c03011"
+version = "1.12.0"
+
+[[deps.KeywordArgumentExtraction]]
+deps = ["ExprTools", "InteractiveUtils"]
+git-tree-sha1 = "e7bb4202f8213e1d10989fc34cb68b3f1687c121"
+uuid = "45533465-3150-2073-4772-41774b207255"
+version = "1.2.0"
+
+[[deps.LazilyInitializedFields]]
+git-tree-sha1 = "0f2da712350b020bc3957f269c9caad516383ee0"
+uuid = "0e77f7df-68c5-4e49-93ce-4cd80f5598bf"
+version = "1.3.0"
+
+[[deps.LazyArtifacts]]
+deps = ["Artifacts", "Pkg"]
+uuid = "4af54fe1-eca0-43a8-85a7-787d91b784e3"
+version = "1.11.0"
+
+[[deps.LazyJLLWrappers]]
+deps = ["Artifacts", "Libdl", "Pkg", "Preferences", "TOML"]
+git-tree-sha1 = "a02a187f0c4c8c9be99b22f8ad5fe41da34ff14f"
+uuid = "21706172-204c-4d4f-5420-656854206f44"
+version = "1.1.0"
+
+[[deps.LibCURL]]
+deps = ["LibCURL_jll", "MozillaCACerts_jll"]
+uuid = "b27032c2-a3e7-50c8-80cd-2d36dbcbfd21"
+version = "0.6.4"
+
+[[deps.LibCURL_jll]]
+deps = ["Artifacts", "LibSSH2_jll", "Libdl", "OpenSSL_jll", "Zlib_jll", "nghttp2_jll"]
+uuid = "deac9b47-8bc7-5906-a0fe-35ac56dc84c0"
+version = "8.15.0+0"
+
+[[deps.LibGit2]]
+deps = ["LibGit2_jll", "NetworkOptions", "Printf", "SHA"]
+uuid = "76f85450-5226-5b5a-8eaa-529ad045b433"
+version = "1.11.0"
+
+[[deps.LibGit2_jll]]
+deps = ["Artifacts", "LibSSH2_jll", "Libdl", "OpenSSL_jll"]
+uuid = "e37daf67-58a4-590a-8e99-b0245dd2ffc5"
+version = "1.9.0+0"
+
+[[deps.LibSSH2_jll]]
+deps = ["Artifacts", "Libdl", "OpenSSL_jll"]
+uuid = "29816b5a-b9ab-546f-933c-edad1886dfa8"
+version = "1.11.3+1"
+
+[[deps.Libdl]]
+uuid = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
+version = "1.11.0"
+
+[[deps.Libiconv_jll]]
+deps = ["Artifacts", "JLLWrappers", "Libdl"]
+git-tree-sha1 = "be484f5c92fad0bd8acfef35fe017900b0b73809"
+uuid = "94ce4f54-9a6c-5748-9c1c-f9c7231a4531"
+version = "1.18.0+0"
+
+[[deps.LicenseCheck]]
+deps = ["licensecheck_jll"]
+git-tree-sha1 = "9c36d53a16450b2302720c822c62b0fb903d5df7"
+uuid = "726dbf0d-6eb6-41af-b36c-cd770e0f00cc"
+version = "0.2.3"
+
+[[deps.LocalRegistry]]
+deps = ["Random", "RegistryInstances", "RegistryTools", "TOML", "UUIDs"]
+git-tree-sha1 = "80d096310838ebd9dfbe7934034da35c26ff4df4"
+uuid = "89398ba2-070a-4b16-a995-9893c55d93cf"
+version = "0.5.7"
+
+[[deps.Logging]]
+uuid = "56ddb016-857b-54e1-b83d-db4d58db5568"
+version = "1.11.0"
+
+[[deps.LoggingExtras]]
+deps = ["Dates", "Logging"]
+git-tree-sha1 = "f00544d95982ea270145636c181ceda21c4e2575"
+uuid = "e6f89c97-d47a-5376-807f-9c37f3926c36"
+version = "1.2.0"
+
+[[deps.Markdown]]
+deps = ["Base64", "JuliaSyntaxHighlighting", "StyledStrings"]
+uuid = "d6f4376e-aef5-505a-96c1-9c027394607a"
+version = "1.11.0"
+
+[[deps.MozillaCACerts_jll]]
+uuid = "14a3606d-f60d-562e-9121-12d972cd8159"
+version = "2025.11.4"
+
+[[deps.MultiHashParsing]]
+deps = ["SHA"]
+git-tree-sha1 = "5b50aad47daa2f19b61fae3abb3bfe431eff1347"
+uuid = "73786568-6863-756d-6873-6168796e616d"
+version = "0.2.1"
+
+[[deps.NetworkOptions]]
+uuid = "ca575930-c2e3-43a9-ace4-1e988b2c1908"
+version = "1.3.0"
+
+[[deps.ObjectFile]]
+deps = ["Reexport", "StructIO"]
+git-tree-sha1 = "09b1fe6ff16e6587fa240c165347474322e77cf1"
+uuid = "d8793406-e978-5875-9003-1fc021f44a92"
+version = "0.4.4"
+
+[[deps.OpenSSH_jll]]
+deps = ["Artifacts", "JLLWrappers", "Libdl", "OpenSSL_jll", "Zlib_jll"]
+git-tree-sha1 = "57baa4b81a24c2910afbb6d853aa0685e4312bf7"
+uuid = "9bd350c2-7e96-507f-8002-3f2e150b4e1b"
+version = "10.3.1+0"
+
+[[deps.OpenSSL_jll]]
+deps = ["Artifacts", "Libdl"]
+uuid = "458c3c95-2e84-50aa-8efc-19380b2a3a95"
+version = "3.5.4+0"
+
+[[deps.OrderedCollections]]
+git-tree-sha1 = "05868e21324cede2207c6f0f466b4bfef6d5e7ee"
+uuid = "bac558e1-5e72-5ebc-8fee-abe8a469f55d"
+version = "1.8.1"
+
+[[deps.OutputCollectors]]
+deps = ["StyledStrings"]
+git-tree-sha1 = "eb19f9f90e662259412f4e17bbab2b7d6292c503"
+uuid = "6c11c7d4-943b-4e2b-80de-f2cfc2930a8c"
+version = "1.0.0"
+
+[[deps.PCRE2_jll]]
+deps = ["Artifacts", "Libdl"]
+uuid = "efcefdf7-47ab-520b-bdef-62a2eaa19f15"
+version = "10.44.0+1"
+
+[[deps.Pkg]]
+deps = ["Artifacts", "Dates", "Downloads", "FileWatching", "LibGit2", "Libdl", "Logging", "Markdown", "Printf", "Random", "SHA", "TOML", "Tar", "UUIDs", "p7zip_jll"]
+uuid = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
+version = "1.12.1"
+weakdeps = ["REPL"]
+
+    [deps.Pkg.extensions]
+    REPLExt = "REPL"
+
+[[deps.PrecompileTools]]
+deps = ["Preferences"]
+git-tree-sha1 = "07a921781cab75691315adc645096ed5e370cb77"
+uuid = "aea7be01-6a6a-4083-8856-8a6e6704d82a"
+version = "1.3.3"
+
+[[deps.Preferences]]
+deps = ["TOML"]
+git-tree-sha1 = "8b770b60760d4451834fe79dd483e318eee709c4"
+uuid = "21216c6a-2e73-6563-6e65-726566657250"
+version = "1.5.2"
+
+[[deps.Printf]]
+deps = ["Unicode"]
+uuid = "de0858da-6303-5e67-8744-51eddeeeb8d7"
+version = "1.11.0"
+
+[[deps.REPL]]
+deps = ["InteractiveUtils", "JuliaSyntaxHighlighting", "Markdown", "Sockets", "StyledStrings", "Unicode"]
+uuid = "3fa0cd96-eef1-5676-8a61-b3b8758bbffb"
+version = "1.11.0"
+
+[[deps.Random]]
+deps = ["SHA"]
+uuid = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
+version = "1.11.0"
+
+[[deps.Reexport]]
+git-tree-sha1 = "45e428421666073eab6f2da5c9d310d99bb12f9b"
+uuid = "189a3867-3050-52da-a836-e630ba90ab69"
+version = "1.2.2"
+
+[[deps.RegistryInstances]]
+deps = ["LazilyInitializedFields", "Pkg", "TOML", "Tar"]
+git-tree-sha1 = "ffd19052caf598b8653b99404058fce14828be51"
+uuid = "2792f1a3-b283-48e8-9a74-f99dce5104f3"
+version = "0.1.0"
+
+[[deps.RegistryTools]]
+deps = ["LibGit2", "Pkg", "SHA", "UUIDs"]
+git-tree-sha1 = "c887ec1a5f4fe2872dfa01640a1dd2050fac48f4"
+uuid = "d1eb7eb1-105f-429d-abf5-b0f65cb9e2c4"
+version = "2.4.3"
+
+[[deps.SHA]]
+uuid = "ea8e919c-243c-51af-8825-aaa63cd721ce"
+version = "0.7.0"
+
+[[deps.Sandbox]]
+deps = ["EnumX", "LazyArtifacts", "Libdl", "Preferences", "Random", "SHA", "Scratch", "TOML", "Tar", "Tar_jll", "UserNSSandbox_jll"]
+git-tree-sha1 = "0ef566f01a76acf5a98f1371e05e07ebec2e982a"
+uuid = "9307e30f-c43e-9ca7-d17c-c2dc59df670d"
+version = "2.1.3"
+
+[[deps.Scratch]]
+deps = ["Dates"]
+git-tree-sha1 = "9b81b8393e50b7d4e6d0a9f14e192294d3b7c109"
+uuid = "6c6a2e73-6563-6170-7368-637461726353"
+version = "1.3.0"
+
+[[deps.ScratchSpaceGarbageCollector]]
+deps = ["Dates", "Scratch", "TOML"]
+git-tree-sha1 = "23fb4904a86f00eff119865bbbbc0a8f58928ef3"
+uuid = "2b218182-314f-4389-a4eb-69d351d2272a"
+version = "0.1.1"
+
+[[deps.Serialization]]
+uuid = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
+version = "1.11.0"
+
+[[deps.Sockets]]
+uuid = "6462fe0b-24de-5631-8697-dd941f90decc"
+version = "1.11.0"
+
+[[deps.StringEncodings]]
+deps = ["Libiconv_jll"]
+git-tree-sha1 = "b765e46ba27ecf6b44faf70df40c57aa3a547dcb"
+uuid = "69024149-9ee7-55f6-a4c4-859efe599b68"
+version = "0.3.7"
+
+[[deps.StructEquality]]
+deps = ["Compat"]
+git-tree-sha1 = "192a9f1de3cfef80ab1a4ba7b150bb0e11ceedcf"
+uuid = "6ec83bb0-ed9f-11e9-3b4c-2b04cb4e219c"
+version = "2.1.0"
+
+[[deps.StructIO]]
+git-tree-sha1 = "c581be48ae1cbf83e899b14c07a807e1787512cc"
+uuid = "53d494c1-5632-5724-8f4c-31dff12d585f"
+version = "0.3.1"
+
+[[deps.StyledStrings]]
+uuid = "f489334b-da3d-4c2e-b8f0-e476e12c162b"
+version = "1.11.0"
+
+[[deps.TOML]]
+deps = ["Dates"]
+uuid = "fa267f1f-6049-4f14-aa54-33bafae1ed76"
+version = "1.0.3"
+
+[[deps.Tar]]
+deps = ["ArgTools", "SHA"]
+uuid = "a4e569a6-e804-4fa4-b0f3-eef7a1d5b13e"
+version = "1.10.0"
+
+[[deps.Tar_jll]]
+deps = ["Artifacts", "Attr_jll", "JLLWrappers", "Libdl", "Libiconv_jll"]
+git-tree-sha1 = "85e7d0ef5248971fbd824f29c52ab6168b895dfd"
+uuid = "9b64493d-8859-5bf3-93d7-7c32dd38186f"
+version = "1.35.0+0"
+
+[[deps.Test]]
+deps = ["InteractiveUtils", "Logging", "Random", "Serialization"]
+uuid = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+version = "1.11.0"
+
+[[deps.TimerOutputs]]
+deps = ["ExprTools", "Printf"]
+git-tree-sha1 = "3748bd928e68c7c346b52125cf41fff0de6937d0"
+uuid = "a759f4b9-e2f1-59dc-863e-4aeb61b1ea8f"
+version = "0.5.29"
+
+    [deps.TimerOutputs.extensions]
+    FlameGraphsExt = "FlameGraphs"
+
+    [deps.TimerOutputs.weakdeps]
+    FlameGraphs = "08572546-2f56-4bcf-ba4e-bab62c3a3f89"
+
+[[deps.TreeArchival]]
+deps = ["SHA", "Tar", "Tar_jll", "Zstd_jll", "p7zip_jll"]
+git-tree-sha1 = "c8fdba0b5836047e2060b887da3761effa6f6864"
+uuid = "216c6a2e-6c61-7669-6863-726165657274"
+version = "0.2.0"
+
+[[deps.UUIDs]]
+deps = ["Random", "SHA"]
+uuid = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
+version = "1.11.0"
+
+[[deps.Unicode]]
+uuid = "4ec0a83e-493e-50e2-b9ac-8f72acf5a8f5"
+version = "1.11.0"
+
+[[deps.UserNSSandbox_jll]]
+deps = ["Artifacts", "JLLWrappers", "Libdl"]
+git-tree-sha1 = "79dc57555c873394aa67457f9c6022068da7b04a"
+uuid = "b88861f7-1d72-59dd-91e7-a8cc876a4984"
+version = "2025.1.28+0"
+
+[[deps.YAML]]
+deps = ["Base64", "Dates", "Printf", "StringEncodings"]
+git-tree-sha1 = "a1c0c7585346251353cddede21f180b96388c403"
+uuid = "ddb6d928-2868-570f-bddf-ab3f9cf99eb6"
+version = "0.4.16"
+
+[[deps.Zlib_jll]]
+deps = ["Libdl"]
+uuid = "83775a58-1f1d-513f-b197-d71354ab007a"
+version = "1.3.1+2"
+
+[[deps.Zstd_jll]]
+deps = ["Artifacts", "JLLWrappers", "Libdl"]
+git-tree-sha1 = "446b23e73536f84e8037f5dce465e92275f6a308"
+uuid = "3161d3a3-bdf6-5164-811a-617609db77b4"
+version = "1.5.7+1"
+
+[[deps.gh_cli_jll]]
+deps = ["Artifacts", "JLLWrappers", "Libdl"]
+git-tree-sha1 = "894b4ad6ac54832386f8d01e84cab691b588f364"
+uuid = "5d31d589-30fb-542f-b82d-10325e863e38"
+version = "2.83.2+0"
+
+[[deps.licensecheck_jll]]
+deps = ["Artifacts", "JLLWrappers", "Libdl"]
+git-tree-sha1 = "ec4140cff0cecddeb1bcf0253194ea655bae1c21"
+uuid = "4ecb348a-8b88-51ea-b912-4c460483ee91"
+version = "0.4.0+0"
+
+[[deps.nghttp2_jll]]
+deps = ["Artifacts", "Libdl"]
+uuid = "8e850ede-7688-5339-a07c-302acd2aaf8d"
+version = "1.64.0+1"
+
+[[deps.p7zip_jll]]
+deps = ["Artifacts", "CompilerSupportLibraries_jll", "Libdl"]
+uuid = "3f19e933-33d8-53b3-aaab-bd5110c3b7a0"
+version = "17.7.0+0"
diff --git a/.ci/bb2_project/Project.toml b/.ci/bb2_project/Project.toml
new file mode 100644
index 00000000000..105ef0b97e1
--- /dev/null
+++ b/.ci/bb2_project/Project.toml
@@ -0,0 +1,3 @@
+[deps]
+BinaryBuilder2 = "12aac903-9f7c-5d81-afc2-d9565ea332af"
+YAML = "ddb6d928-2868-570f-bddf-ab3f9cf99eb6"
diff --git a/.ci/bb2_project/build_test.jl b/.ci/bb2_project/build_test.jl
new file mode 100644
index 00000000000..22155c8000c
--- /dev/null
+++ b/.ci/bb2_project/build_test.jl
@@ -0,0 +1,76 @@
+# This script is meant to run a simple test of the BB2 Yggdrasil build integration
+using YAML
+
+# Mark ourselves as a pull request by default.  The `git branch` thing
+# is so that `generator.jl` can get a commit message for this fictitious pull request.
+ENV["BUILDKITE_PULL_REQUEST"] = "-1"
+run(`git branch -f origin/pr/-1`)
+
+YGGDRASIL_BASE = dirname(dirname(@__DIR__))
+
+# Load YAML definition of buildkite job
+yaml = YAML.load(readchomp(
+    Cmd(`$(Base.julia_cmd()) --project .buildkite/generator.jl H/HelloWorldCxx`;
+        dir=YGGDRASIL_BASE
+    )
+))
+
+function run_buildkite_cmd(cmd)
+    env = copy(ENV)
+    env["JULIA_PROJECT"] = @__DIR__
+    return run(Cmd(`/bin/bash -c $(cmd)`; dir=YGGDRASIL_BASE, env))
+end
+
+# We're going to "upload" our build products to this archive folder
+# This also preserves the artifacts from our `clean_products.sh` script
+archive_dir = joinpath(YGGDRASIL_BASE, "archive")
+mkpath(archive_dir)
+
+# Run all the build steps
+for bk_group in yaml["steps"]
+    for bk_step in bk_group["steps"]
+        continue
+        if !startswith(bk_step["label"], "build")
+            continue
+        end
+
+        for cmd in bk_step["commands"]
+            @info(bk_step["label"])
+            run_buildkite_cmd(cmd)
+
+            # Now, "upload those builds"
+            products_dir = joinpath(YGGDRASIL_BASE, bk_group["group"], "products")
+            for file in readdir(products_dir)
+                @info("Upload: ", file)
+                mv(joinpath(products_dir, file), joinpath(archive_dir, file))
+            end
+        end
+    end
+end
+
+# Now we're going to run the register steps
+for bk_group in yaml["steps"]
+    for bk_step in bk_group["steps"]
+        if !startswith(bk_step["label"], "register")
+            println("skipping $(bk_step["label"])")
+            continue
+        end
+
+        # "download" the artifacts
+        products_dir = joinpath(YGGDRASIL_BASE, bk_group["group"], "products")
+        for file in readdir(archive_dir)
+            @info("Download: ", file)
+            cp(joinpath(archive_dir, file), joinpath(products_dir, file))
+        end
+
+        # Run registration
+        for cmd in bk_step["commands"]
+            @info(bk_step["label"])
+            run_buildkite_cmd(cmd)
+        end
+    end
+end
+
+
+# Cleanup our fake branch
+run(`git branch -d origin/pr/-1`)
diff --git a/.ci/bb2_project/extract_artifacts.jl b/.ci/bb2_project/extract_artifacts.jl
new file mode 100644
index 00000000000..241284a6806
--- /dev/null
+++ b/.ci/bb2_project/extract_artifacts.jl
@@ -0,0 +1,3 @@
+using BinaryBuilder2
+
+# Load in the set of artifacts,
diff --git a/.ci/bb2_project/register_package.jl b/.ci/bb2_project/register_package.jl
new file mode 100644
index 00000000000..0cdd27e534b
--- /dev/null
+++ b/.ci/bb2_project/register_package.jl
@@ -0,0 +1,13 @@
+using BinaryBuilder2
+using BinaryBuilder2: import_archives
+
+meta = BuildMeta(;
+    deploy_org="JuliaBinaryWrappers",
+    register=true,
+)
+
+# Import archives from `products`
+import_archives(meta.build_cache, "products")
+
+# Then run build_tarballs.jl; this shouldn't build anything
+run_build_tarballs(meta, "build_tarballs.jl")
diff --git a/.ci/bb2_project/scheduler.jl b/.ci/bb2_project/scheduler.jl
new file mode 100644
index 00000000000..5fd8aa27108
--- /dev/null
+++ b/.ci/bb2_project/scheduler.jl
@@ -0,0 +1,72 @@
+using BinaryBuilder2, YAML
+
+# Given a list of projects (which each have a `build_tarballs.jl` file), use BB2's dry-run capability
+# to get a list of `BuildConfig` objects.  We will then emit a structured output back to the calling
+# script that allows it to emit buildkite jobs.
+
+# Start by ingesting all build_tarballs into `meta`
+const YGGDRASIL_BASE = dirname(dirname(@__DIR__))
+meta = BuildMeta(; verbose=false, dry_run=["build"])
+for project in ARGS
+    run_build_tarballs(meta, joinpath(YGGDRASIL_BASE, project, "build_tarballs.jl"))
+end
+
+package_names = [package_config.name for package_config in keys(meta.packagings)]
+function get_dep_names(pr::PackageResult)
+    dep_names = String[]
+    for er in first.(values(pr.config.named_extractions))
+        for ts in er.config.build.config.target_specs
+            for dep in ts.dependencies
+                if !isa(dep, JLLSource)
+                    continue
+                end
+
+                dep_name = BinaryBuilder2.strip_jll_suffix(dep.package.name)
+                if dep_name ∈ package_names
+                    push!(dep_names, dep_name)
+                end
+            end
+        end
+    end
+    return dep_names
+end
+
+function project_path(build_result::BuildResult)
+    build_script_path = build_result.config.build_script_path
+    if isfile(build_script_path)
+       build_script_path = dirname(build_script_path) 
+    end
+    return relpath(build_script_path, YGGDRASIL_BASE)
+end
+
+
+# Next, iterate over `PackageResult` objects; each `PackageResult` will become a registration job,
+# and the `BuildConfig`'s from each `PackageResult` will become a build job.  Note that we
+# deduplicate `BuildConfig`'s because it's possible for a single build to be packaged into multiple
+# separate JLLs.
+
+groups = Dict()
+get_group(name) = get!(groups, name, Dict("builds" => [], "packagings" => []))
+
+for (_, package_result) in meta.packagings
+    package_deps = get_dep_names(package_result)
+    for build_result in collect_builds(package_result)
+        group = get_group(project_path(build_result))
+        push!(group["builds"], Dict(
+            "name" => build_result.config.src_name,
+            "script" => build_result.config.build_script_path,
+            "build_hash" => spec_hash(build_result.config),
+            "platform" => triplet(BinaryBuilder2.get_default_target_spec(build_result.config).platform.target),
+            "dependencies" => package_deps,
+        ))
+    end
+    group = get_group(project_path(first(collect_builds(package_result))))
+    push!(group["packagings"], Dict(
+        "name" => package_result.config.name,
+        "dependencies" => package_deps,
+    ))
+end
+
+# Emit structured output that our caller can interpret.
+# We use YAML because it already exists in the `.buildkite` project
+YAML.write(stdout, groups)
diff --git a/.ci/bb2_project/test.sh b/.ci/bb2_project/test.sh
new file mode 100755
index 00000000000..236f1de3e50
--- /dev/null
+++ b/.ci/bb2_project/test.sh
@@ -0,0 +1,5 @@
+#!/bin/bash
+
+for x in "$@"; do
+    echo "$x"
+done
diff --git a/.github/workflows/update_manifest.yml b/.github/workflows/update_manifest.yml
index e90208988cd..8804c51c6a2 100644
--- a/.github/workflows/update_manifest.yml
+++ b/.github/workflows/update_manifest.yml
@@ -30,7 +30,7 @@ jobs:
           Pkg.instantiate()
           Pkg.precompile()
       - name: Generate commit message
-        run: julia --project=.ci --color=yes .ci/update_manifest.jl
+        run: julia --project=.ci/bb1_project --color=yes .ci/bb1_project/update_manifest.jl
         id: commit_message
       - name: Show git status
         run: git status
diff --git a/.gitignore b/.gitignore
index 305d2f4a9f7..d4ba67e9006 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,5 +1,6 @@
 # Ignore intermediate and final build products
 build/
+archive/
 */**/build
 */**/products
 
@@ -7,7 +8,8 @@ build/
 *.swp
 
 # Ignore meta.json files
-meta.json
+*.meta.json
+*.platform.list
 
 .DS_Store
 
diff --git a/H/HelloWorldC/build_tarballs.jl b/H/HelloWorldC/build_tarballs.jl
index 2fbe0c62d73..89d42141737 100644
--- a/H/HelloWorldC/build_tarballs.jl
+++ b/H/HelloWorldC/build_tarballs.jl
@@ -1,7 +1,7 @@
 using BinaryBuilder
 
 name = "HelloWorldC"
-version = v"1.4.1"
+version = v"1.4.2"
 
 # No sources, we're just building the testsuite
 sources = [
diff --git a/H/HelloWorldCxx/build_tarballs.jl b/H/HelloWorldCxx/build_tarballs.jl
index 50bd39d9288..5d922a5b437 100644
--- a/H/HelloWorldCxx/build_tarballs.jl
+++ b/H/HelloWorldCxx/build_tarballs.jl
@@ -1,16 +1,17 @@
-using BinaryBuilder
+using BinaryBuilder2, BinaryBuilder2.Compat
 
 name = "HelloWorldCxx"
-version = v"1.1.1"
+version = v"1.1.2"
 
 # No sources, we're just building the testsuite
 sources = [
+    DirectorySource("./bundled"),
 ]
 
 # Bash recipe for building across all platforms
 script = raw"""
 mkdir -p ${prefix}/bin
-c++ -o ${prefix}/bin/hello_world${exeext} -g -O2 /usr/share/testsuite/cxx/hello_world/hello_world.cc
+c++ -o ${prefix}/bin/hello_world${exeext} -g -O2 hello_world.cc
 install_license /usr/share/licenses/MIT
 """
 
diff --git a/H/HelloWorldCxx/bundled/hello_world.cc b/H/HelloWorldCxx/bundled/hello_world.cc
new file mode 100644
index 00000000000..5309443c087
--- /dev/null
+++ b/H/HelloWorldCxx/bundled/hello_world.cc
@@ -0,0 +1,6 @@
+#include <iostream>
+
+int main(void) {
+    std::cout << "Hello, World!\n";
+    return 0;
+}