diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index 77328e35..40e41e6a 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -15,17 +15,31 @@ permissions:
 
 jobs:
   build:
-    name: build kernel #and system
+    name: build kernel and system
     runs-on: namespace-profile-arm64-8x16-2004-caching
-    timeout-minutes: 20
+    timeout-minutes: 60
     steps:
     - uses: actions/checkout@v4
       with:
         lfs: true
 
-    - name: get kernel submodule ref
+    - name: Get commit message
+      run: |
+        {
+          echo 'LAST_COMMIT_MESSAGE<<EOF'
+          if [ "${{ github.event_name }}" == "push" ]; then
+            echo "${{ github.event.head_commit.message }}"
+          elif [ "${{ github.event_name }}" == "workflow_run" ]; then
+            echo "${{ github.event.workflow_run.head_commit.message }}"
+          elif [ "${{ github.event_name }}" == "pull_request" ]; then
+            echo "$(curl -s '${{ github.event.pull_request.commits_url }}' | jq -r '.[-1].commit.message')"
+          fi
+          echo EOF
+        } | tee -a $GITHUB_ENV
+    
+    - name: Get kernel submodule ref
       id: kernel-submodule
-      run: echo "ref=$(git ls-tree HEAD | awk '$4 == "agnos-kernel-sdm845"' | awk '{print $3}')" >> "$GITHUB_OUTPUT"
+      run: echo "ref=$(git ls-tree HEAD | awk '$4 == "agnos-kernel-sdm845"' | awk '{print $3}')" | tee -a $GITHUB_OUTPUT
 
     - name: Checkout agnos-kernel-sdm845
       uses: actions/checkout@v4
@@ -34,6 +48,13 @@ jobs:
         ref: ${{ steps.kernel-submodule.outputs.ref }}
         path: agnos-kernel-sdm845
 
+    - name: ccache
+      uses: hendrikmuhs/ccache-action@c92f40bee50034e84c763e33b317c77adaa81c92
+      with:
+        create-symlink: true
+        key: kernel-ccache-${{ steps.kernel-submodule.outputs.ref }}
+        restore-keys: kernel-ccache-
+
     - name: Install dependencies
       run: sudo apt-get update && sudo apt-get install -y bc img2simg
 
@@ -42,29 +63,29 @@ jobs:
       with:
         default: '2.7.18'
 
-    - name: Cache kernel build
-      uses: actions/cache@v4
-      id: cache-kernel
-      with:
-        key: kernel-${{ steps.kernel-submodule.outputs.ref }}
-        path: |
-          agnos-kernel-sdm845/out
-        restore-keys: kernel-
-
     - name: Build kernel
       run: ./build_kernel.sh
 
-    - uses: actions/upload-artifact@v4
+    - name: Upload artifact boot.img
+      uses: actions/upload-artifact@v4
+      if: "contains(env.LAST_COMMIT_MESSAGE, '[upload]')"
       with:
         name: boot.img
         path: output/boot.img
-    - uses: actions/upload-artifact@v4
+
+    - name: Upload artifact kernel modules
+      uses: actions/upload-artifact@v4
+      if: "contains(env.LAST_COMMIT_MESSAGE, '[upload]')"
       with:
         name: kernel-modules
         path: output/*.ko
 
-    #- run: ./build_system.sh
-    #- uses: actions/upload-artifact@v4
-    #  with:
-    #    name: system.img
-    #    path: output/system.img
+    - name: Build system
+      run: ./build_system.sh
+
+    - name: Upload artifact system.img
+      uses: actions/upload-artifact@v4
+      if: "contains(env.LAST_COMMIT_MESSAGE, '[upload]')"
+      with:
+        name: system.img
+        path: output/system.img
diff --git a/build_system.sh b/build_system.sh
index e617d76f..bc4b5156 100755
--- a/build_system.sh
+++ b/build_system.sh
@@ -22,9 +22,9 @@ SKIP_CHUNKS_IMAGE="$OUTPUT_DIR/system-skip-chunks.img"
 # Create temp dir if non-existent
 mkdir -p $BUILD_DIR $OUTPUT_DIR
 
-# Copy kernel modules over
+# Copy kernel modules
 if ! ls $OUTPUT_DIR/*.ko >/dev/null 2>&1; then
-  echo "kernel modules missing. run ./build_kernel.sh first"
+  echo "Kernel modules missing. Run ./build_kernel.sh first"
   exit 1
 fi
 cp $OUTPUT_DIR/wlan.ko $DIR/userspace/usr/comma
@@ -33,7 +33,7 @@ cp $OUTPUT_DIR/snd*.ko $DIR/userspace/usr/comma/sound/
 # Download Ubuntu Base if not done already
 if [ ! -f $UBUNTU_FILE ]; then
   echo -e "${GREEN}Downloading Ubuntu: $UBUNTU_FILE ${NO_COLOR}"
-  curl -C - -o $UBUNTU_FILE $UBUNTU_BASE_URL/$UBUNTU_FILE --silent
+  curl -C - -o $UBUNTU_FILE $UBUNTU_BASE_URL/$UBUNTU_FILE --silent --remote-time
 fi
 
 # Register qemu multiarch