diff --git a/action.yml.erb b/action.yml.erb
index 226285b..39c72fd 100644
--- a/action.yml.erb
+++ b/action.yml.erb
@@ -16,9 +16,9 @@ inputs:
     required: false
     default: true
   build_revision:
-    description: 'The SHA-1 of the git commit for which the build is running. Default to GITHUB_SHA when not provided.'
+    description: 'The SHA-1 of the git commit for which the build is running. Default to GITHUB_SHA.'
     required: false
-    default:
+    default: ${{ github.sha }}
   verbose:
     description: 'Verbose output'
     required: false
diff --git a/entrypoint.sh b/entrypoint.sh
index 71d3c51..bb396ea 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -17,7 +17,7 @@ GITHUB_PAGES=$PAGES_GEM_HOME/bin/github-pages
 export JEKYLL_ENV="production"
 export JEKYLL_GITHUB_TOKEN=$INPUT_TOKEN
 export PAGES_REPO_NWO=$GITHUB_REPOSITORY
-export JEKYLL_BUILD_REVISION=${INPUT_BUILD_REVISION:="$GITHUB_SHA"}
+export JEKYLL_BUILD_REVISION=$INPUT_BUILD_REVISION
 
 # Set verbose flag
 if [ "$INPUT_VERBOSE" = 'true' ]; then