diff --git a/.github/workflows/docker-publish.yml b/.github/workflows/docker-publish.yml
index 0fca896..1cf9e34 100644
--- a/.github/workflows/docker-publish.yml
+++ b/.github/workflows/docker-publish.yml
@@ -50,7 +50,7 @@ jobs:
             type=semver,pattern={{version}}
             type=semver,pattern={{major}}.{{minor}}
             type=semver,pattern={{major}}
-            type=sha,prefix={{branch}}-
+            type=sha
             type=raw,value=latest,enable={{is_default_branch}}
 
       - name: Build Docker image
diff --git a/Dockerfile b/Dockerfile
index abc6629..dfc6c47 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -18,6 +18,10 @@ RUN make init
 # Runtime stage - use Alpine for minimal size
 FROM alpine:3.19
 
+# Install file command for testing init binary
+# file package provides the file(1) command to determine file type
+RUN apk add --no-cache file
+
 # Note: Alpine includes busybox by default
 
 # Create minimal rootfs structure
@@ -65,7 +69,11 @@ if [ -f /sparkos/rootfs/sbin/init ]; then
     ls -lh /sparkos/rootfs/sbin/init
     echo ""
     echo "File type:"
-    file /sparkos/rootfs/sbin/init
+    if command -v file >/dev/null 2>&1; then
+        file /sparkos/rootfs/sbin/init
+    else
+        echo "  (file command not available)"
+    fi
     echo ""
     echo "Dependencies:"
     ldd /sparkos/rootfs/sbin/init 2>&1 || echo "  Static binary (no dependencies)"