diff --git a/live-build/auto/config b/live-build/auto/config
index 6d4b9086..75fd11aa 100755
--- a/live-build/auto/config
+++ b/live-build/auto/config
@@ -191,7 +191,7 @@ case $IMAGEFORMAT in
 				;;
 			*)
 				# Ubuntu Core 18
-				MODEL="ubuntu-core-18-$MODEL" ;;
+				MODEL="ubuntu-core-18-${MODEL#pc-}" ;;
 		esac
 
 		echo "IMAGEFORMAT=$IMAGEFORMAT" >> config/common