build linux executables too

.github/workflows/build.yml

@@ -133,6 +133,48 @@ jobs:
         path: firmware
         key: cache-firmware-esp32-repeaters-${{ github.sha }}
 
+  build-linux:
+    needs: setup-zephyr
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v6
+
+    - uses: actions/setup-python@v6
+      with:
+        python-version: '${{ env.python_version }}'
+        cache: 'pip'
+    - run: pip install -r requirements.txt
+
+    - uses: actions/cache/restore@v5
+      with:
+        path: modules
+        key: cache-zephyr-modules-${{ github.sha }}
+
+    - name: Setup Zephyr project
+      uses: zephyrproject-rtos/action-zephyr-setup@v1
+      with:
+        app-path: zephcore
+        toolchains: ${{ env.toolchains }}
+        sdk-version: ${{ env.zephyr_sdk }}
+
+    # native_sim presets are cross-compiled for the target SBC architecture:
+    # femtofox = ARMv7-A (32-bit), rak6421 / rak6421_pi5 = aarch64 (64-bit).
+    - name: Install cross-compile toolchains
+      run: |
+        sudo apt-get update
+        sudo apt-get install -y \
+          gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf \
+          gcc-aarch64-linux-gnu   g++-aarch64-linux-gnu
+
+    - name: build firmwares
+      run: bash build.sh linux
+
+    - uses: actions/cache@v5
+      with:
+        path: firmware
+        key: cache-firmware-linux-${{ github.sha }}
+
   build-esp32-companions:
     needs: setup-zephyr
     runs-on: ubuntu-latest
@@ -178,7 +220,7 @@ jobs:
         key: cache-firmware-esp32-companions-${{ github.sha }}
 
   create-release:
-    needs: [build-nrf, build-esp32-companions, build-esp32-repeaters]
+    needs: [build-nrf, build-esp32-companions, build-esp32-repeaters, build-linux]
     runs-on: ubuntu-latest
 
     steps:
@@ -203,6 +245,11 @@ jobs:
         path: firmware
         key: cache-firmware-esp32-repeaters-${{ github.sha }}
 
+    - uses: actions/cache/restore@v5
+      with:
+        path: firmware
+        key: cache-firmware-linux-${{ github.sha }}
+
     - name: upload firmware artifacts
       uses: actions/upload-artifact@v7
       with:

build.sh

@@ -23,6 +23,14 @@ nRF_boards=(
     gat562_30s
 )
 
+# Native-Linux presets (not Zephyr boards — built with -b native_sim plus an
+# EXTRA_CONF_FILE). Each targets a real SBC arch, so it is cross-compiled.
+Linux_boards=(
+    femtofox
+    rak6421
+    rak6421_pi5
+)
+
 ESP32_boards=(
     xiao_esp32c3
     xiao_esp32c6/esp32c6/hpcore
@@ -71,6 +79,50 @@ if [[ $1 == "nrf" ]]; then
     done
 fi
 
+if [[ $1 == "linux" ]]; then
+    for board in "${Linux_boards[@]}"; do
+        # Pick the native_sim variant + cross toolchain for the target SBC arch.
+        case "$board" in
+            femtofox)
+                # Luckfox Pico Mini — ARMv7-A (32-bit) → native_sim (32-bit)
+                zboard="native_sim"
+                host="arm"
+                cross="/usr/bin/arm-linux-gnueabihf-"
+                ;;
+            rak6421|rak6421_pi5)
+                # Raspberry Pi — aarch64 (64-bit) → native_sim/native/64
+                zboard="native_sim/native/64"
+                host="aarch64"
+                cross="/usr/bin/aarch64-linux-gnu-"
+                ;;
+            *)
+                echo "Unknown linux board: $board"
+                exit 1
+                ;;
+        esac
+
+        # build native-Linux companion (TCP transport — the default role)
+        echo "Now building $board companion (native linux)"
+        west build -b "$zboard" zephcore --pristine -- \
+            -DZEPHYR_TOOLCHAIN_VARIANT=cross-compile \
+            -DNATIVE_TARGET_HOST="$host" \
+            -DCROSS_COMPILE="$cross" \
+            -DEXTRA_CONF_FILE="boards/linux_native/$board.conf"
+        # native_sim emits zephcore_native_linux.exe; ship it as an extension-less
+        # per-board name (zephcore_linux_<board>-<role>-<hash>).
+        mv build/zephyr/zephcore_native_linux.exe firmware/zephcore_linux_"$board"-companion-"$COMMIT_HASH"
+
+        # build native-Linux repeater
+        echo "Now building $board repeater (native linux)"
+        west build -b "$zboard" zephcore --pristine -- \
+            -DZEPHYR_TOOLCHAIN_VARIANT=cross-compile \
+            -DNATIVE_TARGET_HOST="$host" \
+            -DCROSS_COMPILE="$cross" \
+            -DEXTRA_CONF_FILE="boards/linux_native/$board.conf;boards/common/repeater.conf"
+        mv build/zephyr/zephcore_native_linux.exe firmware/zephcore_linux_"$board"-repeater-"$COMMIT_HASH"
+    done
+fi
+
 if [[ $1 == "esp32" ]]; then
     for board in "${ESP32_boards[@]}"; do
         board_clean_for_path=$(echo "$board" | sed -e 's/\//-/g')