diff --git a/Config/F-DroidRepo/Dockerfile b/Config/F-DroidRepo/Dockerfile
index b8c3ded..cd5a71e 100644
--- a/Config/F-DroidRepo/Dockerfile
+++ b/Config/F-DroidRepo/Dockerfile
@@ -122,7 +122,7 @@ RUN mv -v "$REPO"/"$REPO_ICON" "$REPO"/icons/ || \
       echo "No PNG files to copy."
 
 # If the icon variable is set, add it to the config file before updating again.
-RUN [[ ! -z "$REPO_ICON" ]] && \
+RUN [ ! -z "$REPO_ICON" ] && \
       sed -i "$ a repo_icon: $REPO_ICON" "$FDROID/config.yml"
 
 RUN fdroid update -c