diff --git a/docker/Dockerfile-alpine-320 b/docker/Dockerfile-alpine-320
index 4745ab4..9acad1e 100644
--- a/docker/Dockerfile-alpine-320
+++ b/docker/Dockerfile-alpine-320
@@ -3,7 +3,7 @@ FROM alpine:3.20
 ENV PATH=/opt/R/4.4.1/bin:$PATH
 ENV TZ="Europe/Berlin"
 
-ENV ARCH=arm64
+ARG ARCH=arm64
 ENV NCPUS=2
 
 ENV AWS_ACCESS_KEY_ID=""