diff --git a/test/others/mnt-ext-dev/run.sh b/test/others/mnt-ext-dev/run.sh
index 368c03d06..9803a8f77 100755
--- a/test/others/mnt-ext-dev/run.sh
+++ b/test/others/mnt-ext-dev/run.sh
@@ -6,7 +6,7 @@ python ../../zdtm.py run -t zdtm/static/env00 --iter 0 -f ns
 
 truncate -s 0 zdtm.loop
 truncate -s 50M zdtm.loop
-mkfs.ext4 zdtm.loop
+mkfs.ext4 -F zdtm.loop
 dev=`losetup --find --show zdtm.loop`
 mkdir -p ../../dev
 cp -ap $dev ../../dev