diff --git a/portainer_agent/Dockerfile b/portainer_agent/Dockerfile
index a64a2ab7d..16875cf31 100644
--- a/portainer_agent/Dockerfile
+++ b/portainer_agent/Dockerfile
@@ -15,9 +15,10 @@
 #################
 
 ARG BUILD_FROM
-FROM $BUILD_FROM
+ENV BUILD_BASE="$BUILD_FROM"
 FROM portainer/agent:alpine as original_agent
 ENV PORTAINER_AGENT_ARGS=""
+FROM "$BUILD_BASE"
 
 # Copy Portainer agent binaries
 COPY --from=original_agent /app /app