diff --git a/test/units/testsuite-70.sh b/test/units/testsuite-70.sh
index 258f39c38d..1f626ee62f 100755
--- a/test/units/testsuite-70.sh
+++ b/test/units/testsuite-70.sh
@@ -5,10 +5,9 @@ set -o pipefail
 
 export SYSTEMD_LOG_LEVEL=debug
 
-
 # Prepare fresh disk image
 img="/var/tmp/test.img"
-dd if=/dev/zero of=$img bs=1024k count=20 status=none
+truncate -s 20M $img
 echo -n passphrase >/tmp/passphrase
 cryptsetup luksFormat -q --pbkdf pbkdf2 --pbkdf-force-iterations 1000 --use-urandom $img /tmp/passphrase