CI: add target to build UEFI-only boot.bin

u-boot and linux should be built using specific tags but let's try this
first to avoid forgetting updating tags.
The workflow runs only on main and for pull request touching it to avoid
failures in pull requests due to u-boot and linux changes.

Signed-off-by: Janne Grunau <[email protected]>

Author: jannau

.github/workflows/installer.yml

@@ -0,0 +1,81 @@
+# This is a basic workflow to help you get started with Actions
+
+name: installer
+
+# Controls when the action will run.
+on:
+  # Triggers the workflow on main branch. Build errors are catched in the
+  # build workflow so failures here are likely caused by the external
+  # sources. No need to run this on pull-requests unless this file is changed.
+  push:
+    branches: [ main ]
+  pull_request:
+    branches: [ main ]
+    paths: [ .github/workflows/installer.yml ]
+
+  # Allows you to run this workflow manually from the Actions tab
+  workflow_dispatch:
+
+jobs:
+  uefi-only-boot-bin:
+    runs-on: ubuntu-latest
+
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          submodules: recursive
+
+      - name: Install aarch64-linux-gnu- toolchain
+        run: |
+          sudo apt-get update
+          sudo apt-get install --no-install-recommends -y \
+                               gcc-aarch64-linux-gnu \
+                               libgnutls28-dev \
+                               device-tree-compiler
+
+      - name: Install nightly rust
+        run: |
+          export RUSTUP_TOOLCHAIN=stable
+          rustup target install aarch64-unknown-none-softfloat
+
+      - name: Build
+        run: make -k -j2 ARCH=aarch64-linux-gnu- RELEASE=1
+
+      - name: Fetch u-boot and downstream device trees
+        run: |
+          mkdir -p uefi-only
+          git clone --depth 1 --no-tags --single-branch -b asahi-releng \
+              https://github.com/AsahiLinux/u-boot.git uefi-only/u-boot
+          git clone --depth=1 --no-tags --single-branch -b asahi \
+              --no-checkout --filter=tree:0 \
+              https://github.com/AsahiLinux/linux.git uefi-only/linux
+          cd uefi-only/linux
+          git sparse-checkout set --no-cone /arch/arm64/boot/dts/apple/
+          git checkout
+
+      - name: Update u-boot apple device trees
+        run: |
+          cp -f uefi-only/linux/arch/arm64/boot/dts/apple/*.dts \
+                uefi-only/linux/arch/arm64/boot/dts/apple/*.dtsi \
+                uefi-only/linux/arch/arm64/boot/dts/apple/*.h \
+                uefi-only/u-boot/arch/arm/dts/
+
+      - name: Build u-boot
+        run: |
+          cd uefi-only/u-boot
+          make CROSS_COMPILE=aarch64-linux-gnu- apple_m1_defconfig
+          make CROSS_COMPILE=aarch64-linux-gnu- ARCH=arm -k -j2
+
+      - name: Create m1n1 uefi only boot.bin
+        run: |
+          gzip -k uefi-only/u-boot/u-boot-nodtb.bin
+          cat build/m1n1.bin \
+              uefi-only/u-boot/arch/arm/dts/t60*.dtb \
+              uefi-only/u-boot/arch/arm/dts/t81*.dtb \
+              > uefi-only/boot.bin
+
+      - uses: actions/upload-artifact@v4
+        with:
+          name: uefi-only_boot.bin
+          path: |
+            uefi-only/boot.bin