diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 49becc70..55da228e 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -28,26 +28,32 @@ jobs:
           - x86-mingw32
           - x64-mingw-ucrt
           - x64-mingw32
-          - x86-linux
+          # - x86-linux
           - x86_64-linux
           - x86_64-darwin
           - arm64-darwin
           - arm-linux
           - aarch64-linux
           - jruby
+        docker-platform-cpu:
+          - amd64
+          - arm64
 
     runs-on: ubuntu-latest
     env:
       PLATFORM: ${{ matrix.platform }}
+      DOCKER_BUILD_PLATFORM: linux/${{ matrix.docker-platform-cpu }}
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
 
       - name: Cache Docker layers
-        uses: actions/cache@v2
+        uses: actions/cache@v3
         with:
           path: tmp/build-cache
-          key: ${{ runner.os }}-${{ matrix.platform }}-buildx-${{ github.sha }}
+          key: ${{ runner.os }}-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}-buildx-${{ github.sha }}
+          # TODO: remove last key
           restore-keys: |
+            ${{ runner.os }}-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}-buildx
             ${{ runner.os }}-${{ matrix.platform }}-buildx
 
       - uses: ruby/setup-ruby@v1
@@ -55,10 +61,37 @@ jobs:
           ruby-version: "3.0"
           bundler-cache: true # runs 'bundle install' and caches installed gems automatically
 
+      - name: Set up QEMU
+        uses: docker/setup-qemu-action@v2
+
       - name: Build docker image
+        id: buildx
         run: |
+          echo "::group::Preparing docker build"
           docker buildx create --driver docker-container --use
-          bundle exec rake build:${PLATFORM} RCD_DOCKER_BUILD="docker buildx build --cache-from=type=local,src=tmp/build-cache --cache-to=type=local,dest=tmp/build-cache-new --load"
+          extra_tag="rcd-${PLATFORM}-${{ matrix.docker-platform-cpu }}-${{ github.sha }}"
+          docker_build="docker buildx build --platform=$DOCKER_BUILD_PLATFORM --cache-from=type=local,src=tmp/build-cache --cache-to=type=local,dest=tmp/build-cache-new --load -t $extra_tag"
+          if bundle exec rake -T | grep -q "prepare:${PLATFORM}"; then
+            echo "::info::Preparing docker image for ${PLATFORM}"
+            bundle exec rake prepare:${PLATFORM} RCD_DOCKER_BUILD="$docker_build"
+          fi
+          echo "::endgroup::"
+
+          bundle exec rake build:${PLATFORM} RCD_DOCKER_BUILD="$docker_build"
+
+          if [[ "${{ contains(github.event.head_commit.message, matrix.docker-platform-cpu) }}" == "true" ]]; then
+            echo "::info::Saving docker image $extra_tag"
+            docker save -o "tmp/${extra_tag}.tar" $extra_tag
+            echo "image-tarball=tmp/${extra_tag}.tar" >> $GITHUB_OUTPUT
+          fi
+
+      - name: Upload Docker image tarball
+        if: ${{ steps.buildx.outputs.image-tarball != '' }}
+        uses: actions/upload-artifact@v3
+        with:
+          name: docker-save-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}-${{ github.sha }}
+          path: ${{ steps.buildx.outputs.image-tarball }}
+          retention-days: 1
 
       - name: Move build cache and remove outdated layers
         run: |
@@ -77,7 +110,7 @@ jobs:
       - name: Upload binary gem
         uses: actions/upload-artifact@v2
         with:
-          name: gem-${{ matrix.platform }}
+          name: gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}
           path: test/rcd_test/pkg/*-*-*.gem
 
       - if: matrix.platform == 'jruby'
@@ -103,11 +136,11 @@ jobs:
         name: Upload static binary gem
         uses: actions/upload-artifact@v2
         with:
-          name: gem-${{ matrix.platform }}-static
+          name: gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}-static
           path: test/rcd_test/pkg/*-*-*.gem
 
   job_test_native:
-    name: Test (${{matrix.ruby}}, ${{matrix.platform}})
+    name: Test (${{matrix.ruby}}, ${{matrix.platform}}, ${{ matrix.docker-platform-cpu }})
     needs: docker_build
     strategy:
       fail-fast: false
@@ -144,16 +177,16 @@ jobs:
 
     runs-on: ${{ matrix.os }}-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
       - run: ruby --version
-      - name: Download gem-${{matrix.platform}}
+      - name: Download gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}
         uses: actions/download-artifact@v2
         with:
-          name: gem-${{ matrix.platform }}
-      - name: Install gem-${{matrix.platform}}
+          name: gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}
+      - name: Install gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}
         run: gem install --local *.gem --verbose
       - name: Run tests
         run: |
@@ -188,16 +221,16 @@ jobs:
 
     runs-on: ${{ matrix.os }}-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: ${{ matrix.ruby }}
       - run: ruby --version
-      - name: Download gem-${{matrix.platform}}-static
+      - name: Download gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}-static
         uses: actions/download-artifact@v2
         with:
-          name: gem-${{ matrix.platform }}-static
-      - name: Install gem-${{matrix.platform}}-static
+          name: gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}-static
+      - name: Install gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}-static
         run: gem install --local *.gem --verbose
       - name: Run tests
         run: |
@@ -230,13 +263,14 @@ jobs:
 
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
-      - name: Download gem-${{matrix.platform}}
+      - uses: actions/checkout@v3
+      - name: Download gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}
         uses: actions/download-artifact@v2
         with:
-          name: gem-${{ matrix.platform }}
+          name: gem-${{ matrix.platform }}-${{ matrix.docker-platform-cpu }}
       - name: Build image and Run tests
         run: |
+          docker buildx create --driver docker-container --use
           docker run --rm --privileged multiarch/qemu-user-static --reset -p yes
-          docker build --rm --build-arg from_image=${{matrix.from_image}} -t ruby-test -f test/env/Dockerfile.${{matrix.dockerfile}} .
-          docker run --rm -t --network=host -v `pwd`:/build ruby-test
+          docker buildx build --platform=$DOCKER_BUILD_PLATFORM --rm --build-arg from_image=${{matrix.from_image}} -t ruby-test -f test/env/Dockerfile.${{matrix.dockerfile}} .
+          docker run --platform=$DOCKER_BUILD_PLATFORM --rm -t --network=host -v `pwd`:/build ruby-test
diff --git a/Dockerfile.mri.erb b/Dockerfile.mri.erb
index 46361869..7df1d281 100644
--- a/Dockerfile.mri.erb
+++ b/Dockerfile.mri.erb
@@ -1,9 +1,11 @@
 <%
 image = case platform
-  when /x86_64-linux/ then "quay.io/pypa/manylinux2014_x86_64"
-  when /x86-linux/ then "quay.io/pypa/manylinux2014_i686"
-  else "ubuntu:20.04"
+  when /x86_64-linux/, /x86-linux/
+    manylinux_image
+  else
+    "ubuntu:20.04"
 end
+
 manylinux = !!(image =~ /manylinux/)
 %>
 FROM <%= image %>
@@ -21,9 +23,13 @@ RUN rm -f /usr/local/bin/sudo && \
     echo "%sudo  ALL=(ALL)       ALL" >> /etc/sudoers
 <% else %>
 ENV DEBIAN_FRONTEND noninteractive
-RUN apt-get -y update && \
-    apt-get install -y sudo wget autoconf cmake curl git-core pkg-config build-essential xz-utils unzip gnupg2 dirmngr zlib1g-dev libreadline-dev libsqlite0-dev libssl-dev libyaml-dev libffi-dev && \
-    rm -rf /var/lib/apt/lists/*
+
+COPY ./build/apt_install_multiarch.sh /
+RUN /apt_install_multiarch.sh <%= foreign_dpkg_arch %> zlib1g-dev libreadline-dev libsqlite0-dev libssl-dev libyaml-dev libffi-dev
+
+RUN apt-get -y -qq update && \
+    apt-get -y -qq install sudo wget autoconf cmake curl git-core pkg-config build-essential xz-utils unzip gnupg2 dirmngr && \
+    rm -rf /var/lib/apt/lists/*;
 <% end %>
 
 # Add "rvm" as system group, to avoid conflicts with host GIDs typically starting with 1000
@@ -74,10 +80,10 @@ USER root
 
 <% if platform=~/x64-mingw-ucrt/ %>
 COPY --from=larskanis/mingw64-ucrt:20.04 \
-    /build/binutils-mingw-w64-x86-64_2.34-6ubuntu1.3+8.8_amd64.deb \
-    /build/g++-mingw-w64-x86-64_9.3.0-17ubuntu1~20.04+22~exp1ubuntu4_amd64.deb \
-    /build/gcc-mingw-w64-base_9.3.0-17ubuntu1~20.04+22~exp1ubuntu4_amd64.deb \
-    /build/gcc-mingw-w64-x86-64_9.3.0-17ubuntu1~20.04+22~exp1ubuntu4_amd64.deb \
+    /build/binutils-mingw-w64-x86-64_2.34-6ubuntu1.3+8.8_<%= host_dpkg_arch %>.deb \
+    /build/g++-mingw-w64-x86-64_9.3.0-17ubuntu1~20.04+22~exp1ubuntu4_<%= host_dpkg_arch %>.deb \
+    /build/gcc-mingw-w64-base_9.3.0-17ubuntu1~20.04+22~exp1ubuntu4_<%= host_dpkg_arch %>.deb \
+    /build/gcc-mingw-w64-x86-64_9.3.0-17ubuntu1~20.04+22~exp1ubuntu4_<%= host_dpkg_arch %>.deb \
     /build/mingw-w64-common_7.0.0-2_all.deb \
     /build/mingw-w64-x86-64-dev_7.0.0-2_all.deb \
     /debs/
diff --git a/Rakefile b/Rakefile
index 6c46f47f..e5b15172 100644
--- a/Rakefile
+++ b/Rakefile
@@ -10,22 +10,45 @@ DOCKERHUB_USER = ENV['DOCKERHUB_USER'] || "larskanis"
 docker_build_cmd = Shellwords.split(ENV['RCD_DOCKER_BUILD'] || "docker build")
 
 platforms = [
-  ["x86-mingw32", "i686-w64-mingw32"],
-  ["x64-mingw32", "x86_64-w64-mingw32"],
-  ["x64-mingw-ucrt", "x86_64-w64-mingw32"],
-  ["x86-linux", "i686-redhat-linux"],
-  ["x86_64-linux", "x86_64-redhat-linux"],
-  ["x86_64-darwin", "x86_64-apple-darwin"],
-  ["arm64-darwin", "aarch64-apple-darwin"],
-  ["arm-linux", "arm-linux-gnueabihf"],
-  ["aarch64-linux", "aarch64-linux-gnu"],
+  ["x86-mingw32", "i686-w64-mingw32", "i386"],
+  ["x64-mingw32", "x86_64-w64-mingw32", "amd64"],
+  ["x64-mingw-ucrt", "x86_64-w64-mingw32", "amd64"],
+  ["x86-linux", "i686-redhat-linux", "i386"],
+  ["x86_64-linux", "x86_64-redhat-linux", "amd64"],
+  ["x86_64-darwin", "x86_64-apple-darwin", "amd64"],
+  ["arm64-darwin", "aarch64-apple-darwin", "arm64"],
+  ["arm-linux", "arm-linux-gnueabihf", "armhf"],
+  ["aarch64-linux", "aarch64-linux-gnu", "arm64"],
 ]
 
 namespace :build do
 
-  platforms.each do |platform, target|
+  platforms.each do |platform, target, foreign_dpkg_arch|
     sdf = "Dockerfile.mri.#{platform}"
 
+    host_dpkg_arch = case ENV["DOCKER_BUILD_PLATFORM"]
+    when /arm64/
+      "arm64"
+    when /amd64/
+      "amd64"
+    else
+      if ENV["CI"]
+        raise "Couldnt infer dpkg arch for #{ENV["DOCKER_BUILD_PLATFORM"].inspect}"
+      else
+        "amd64"
+      end
+    end
+
+    # Native images to alleviate qemu slowness, and manylinux2014 provides per-arch
+    # images. But they are not yet conformant to the Docker platform spec (i.e.
+    # amd64/linux). We generate our own platformed manifests now (using
+    # scrip/remanifest-manylinux-multiplatform.sh), but you should be able to
+    # nuke that code soon, and rely on only the buildx `--platform` feature once
+    # manylinux finishes the feature.
+    #
+    # See: https://github.com/pypa/manylinux/issues/1306
+    manylinux_image = "rbsys/manylinux2014:2022-12-11-145d107"
+
     desc "Build image for platform #{platform}"
     task platform => sdf
     task sdf do
diff --git a/build/apt_install_multiarch.sh b/build/apt_install_multiarch.sh
new file mode 100755
index 00000000..561f816d
--- /dev/null
+++ b/build/apt_install_multiarch.sh
@@ -0,0 +1,39 @@
+#!/bin/bash
+
+set -exuo pipefail
+IFS=$'\n\t'
+
+main() {
+  deb_host_arch="$(dpkg --print-architecture)"
+  lsb_release="$(grep VERSION_CODENAME < /etc/os-release | cut -d= -f2 | tr -d '"')"
+  deb_target_arch="$1"
+
+  shift
+
+  cross_packages=()
+  packages=("$@")
+
+  if [ "$deb_target_arch" != "$deb_host_arch" ] && [ "$deb_host_arch" = "arm64" ]; then
+    echo "Setting up multiarch support for $deb_target_arch" >&2
+    dpkg --add-architecture "$deb_target_arch"
+    cross_packages=("${packages[@]/%/:$deb_target_arch}")
+
+    # Qualify our current source lists to make sure debian doesn't infer stuff
+    sed -i "s/^deb http/deb [arch=$deb_host_arch] http/" /etc/apt/sources.list
+
+    # Add sources for ported target libs
+    echo "deb [arch=$deb_target_arch] http://ports.ubuntu.com/ubuntu-ports $lsb_release main universe restricted multiverse"
+    echo "deb [arch=$deb_target_arch] http://ports.ubuntu.com/ubuntu-ports $lsb_release-updates main universe restricted multiverse"
+    echo "deb [arch=$deb_target_arch] http://ports.ubuntu.com/ubuntu-ports $lsb_release-security main universe restricted multiverse"
+  else
+    echo "No need to set up multiarch support for $deb_target_arch"
+  fi
+
+  apt-get -qq -y update
+  apt-get -qq -y install "${packages[@]}" "${cross_packages[@]}"
+  rm -rf /var/lib/apt/lists/*
+
+  rm "$0"
+}
+
+main "$@"
diff --git a/build/mk_osxcross.sh b/build/mk_osxcross.sh
index 410b84eb..af7ec630 100755
--- a/build/mk_osxcross.sh
+++ b/build/mk_osxcross.sh
@@ -13,7 +13,7 @@ set -x
 curl -L -o MacOSX11.1.sdk.tar.xz https://github.com/larskanis/MacOSX-SDKs/releases/download/11.1/MacOSX11.1.sdk.tar.xz
 tar -xf MacOSX11.1.sdk.tar.xz -C .
 cp -rf /usr/lib/llvm-10/include/c++ MacOSX11.1.sdk/usr/include/c++
-cp -rf /usr/include/x86_64-linux-gnu/c++/9/bits/ MacOSX11.1.sdk/usr/include/c++/v1/bits
+cp -rf /usr/include/"$(uname -m)"-linux-gnu/c++/9/bits/ MacOSX11.1.sdk/usr/include/c++/v1/bits
 tar -cJf MacOSX11.1.sdk.tar.xz MacOSX11.1.sdk
 
 set +x
diff --git a/mingw64-ucrt/Dockerfile b/mingw64-ucrt/Dockerfile
index eb07f5ab..60333c42 100644
--- a/mingw64-ucrt/Dockerfile
+++ b/mingw64-ucrt/Dockerfile
@@ -1,3 +1,4 @@
+
 FROM ubuntu:20.04
 
 ARG DEBIAN_FRONTEND=noninteractive
@@ -32,7 +33,7 @@ RUN cd mingw-w64-* && \
 
 # Install UCRT enabled deb-packages
 RUN dpkg -i mingw-w64-common_7.0.0-2_all.deb \
-    mingw-w64-tools_7.0.0-2_amd64.deb \
+    mingw-w64-tools_7.0.0-2_$(dpkg --print-architecture).deb \
     mingw-w64-x86-64-dev_7.0.0-2_all.deb
 
 # Download gcc-binutils sources for mingw
diff --git a/script/remanifest-manylinux-multiplatform.sh b/script/remanifest-manylinux-multiplatform.sh
new file mode 100755
index 00000000..0e228679
--- /dev/null
+++ b/script/remanifest-manylinux-multiplatform.sh
@@ -0,0 +1,32 @@
+#!/bin/bash
+
+set -euo pipefail
+IFS=$'\n\t'
+
+# A script to build and push a multi-arch image to Docker Hub, based on
+# https://github.com/pypa/manylinux/issues/1306
+
+repo="${DOCKERHUB_USER:-larskanis}"
+tags=("latest" "2022-12-11-145d107")
+base_images=("manylinux2014" "manylinux_2_24")
+
+for base_image in "${base_images[@]}"; do
+  for tag in "${tags[@]}"; do
+    echo Re-manifesting "$base_image":"$tag" >&2
+
+    docker pull --quiet quay.io/pypa/"$base_image"_aarch64:"$tag"
+    docker pull --quiet quay.io/pypa/"$base_image"_x86_64:"$tag"
+
+    docker tag quay.io/pypa/"$base_image"_x86_64:"$tag" "$repo"/"$base_image"_x86_64:"$tag"
+    docker tag quay.io/pypa/"$base_image"_aarch64:"$tag" "$repo"/"$base_image"_aarch64:"$tag"
+
+    docker push --quiet "$repo"/"$base_image"_x86_64:"$tag"
+    docker push --quiet "$repo"/"$base_image"_aarch64:"$tag"
+
+    docker manifest create "$repo"/"$base_image":"$tag" \
+      --amend "$repo"/"$base_image"_x86_64:"$tag" \
+      --amend "$repo"/"$base_image"_aarch64:"$tag"
+
+    docker manifest push "$repo"/"$base_image":"$tag"
+  done
+done