diff --git a/tools/docker/build.sh b/tools/docker/build.sh
index 09627e371..75a1402a9 100755
--- a/tools/docker/build.sh
+++ b/tools/docker/build.sh
@@ -55,7 +55,7 @@ GetQemuArch() {
             ;;
         "*")
             echo "Not supported build architecture '$1'." >&2
-            exit -1
+            exit 1
     esac
 }