diff --git a/test/lib/aux.sh b/test/lib/aux.sh
index 0818675fb..3f66e9290 100644
--- a/test/lib/aux.sh
+++ b/test/lib/aux.sh
@@ -965,7 +965,7 @@ corrupt_dev() {
 	test -n "${a[0]-}" || return 0
 
 	# Seek for the sequence and replace it with corruption pattern
-	echo -n "${a[1]/$2/$3}" | dd of="$1" bs=1 seek="${a[0]}" conv=fdatasync
+	echo -n "${a[1]/$2/$3}" | LANG=C dd of="$1" bs=1 seek="${a[0]}" conv=fdatasync
 }
 
 prepare_backing_dev() {
diff --git a/test/shell/integrity-syncaction.sh b/test/shell/integrity-syncaction.sh
index 72722d693..4bd4accd4 100644
--- a/test/shell/integrity-syncaction.sh
+++ b/test/shell/integrity-syncaction.sh
@@ -53,8 +53,8 @@ _test1() {
 	# Corrupting raid1 is simple - 1 leg needs to be modifed
 	# For raid5 corrupted block can be places on any of its leg.
 	for i in "$@" ; do
-		aux corrupt_dev "$i" BBBBBBBBBBBBBBBBB BBBBBBBBCBBBBBBBB |tee out
-		grep -q "copied" && break  # leg found and corrupted
+		aux corrupt_dev "$i" BBBBBBBBBBBBBBBBB BBBBBBBBCBBBBBBBB |& tee out
+		grep -q "copied" out && break  # leg found and corrupted
 	done
 
 	lvchange -ay $vg/$lv1