diff --git a/podman-build-publish/action.yaml b/podman-build-publish/action.yaml
index 4455484..e06b4a8 100644
--- a/podman-build-publish/action.yaml
+++ b/podman-build-publish/action.yaml
@@ -31,12 +31,6 @@ inputs:
       Example: "ACT_RUNNER_VERSION=0.2.11"
     required: false
     default: ""
-  build-isolation:
-    description: |
-      Podman build isolation mode.
-      Supported values: "chroot" or "oci".
-    required: false
-    default: "chroot"
   push:
     description: |
       Whether to push tags to the registry after build.
@@ -81,15 +75,6 @@ runs:
         echo "PODMAN_STORAGE_DRIVER=${selected_driver}" >> "${GITHUB_ENV}"
         echo "PODMAN_STORAGE_OPT=${selected_storage_opt}" >> "${GITHUB_ENV}"
 
-        case "${{ inputs.build-isolation }}" in
-          chroot|oci)
-            ;;
-          *)
-            echo "ERROR: unsupported build-isolation '${{ inputs.build-isolation }}' (expected 'chroot' or 'oci')" >&2
-            exit 1
-            ;;
-        esac
-
         # Validate tags early so failures are caught before build starts
         mapfile -t tags < <(printf '%s\n' "${{ inputs.tags }}" | tr ', ' '\n\n' | sed '/^$/d')
         if [[ ${#tags[@]} -eq 0 ]]; then
@@ -137,7 +122,7 @@ runs:
         fi
 
         image_base="registry.noctrl.eu/${{ inputs.image-name }}"
-        build_cmd=(podman "${podman_args[@]}" build --isolation "${{ inputs.build-isolation }}" -f "${{ inputs.containerfile }}")
+        build_cmd=(podman "${podman_args[@]}" build --isolation chroot -f "${{ inputs.containerfile }}")
 
         # Add build args
         while IFS= read -r build_arg; do