diff --git a/tests/qemu-iotests/051 b/tests/qemu-iotests/051
index a13bce2fd0..d7294d80d9 100755
--- a/tests/qemu-iotests/051
+++ b/tests/qemu-iotests/051
@@ -158,7 +158,7 @@ echo
 echo === With version 2 images enabling lazy refcounts must fail ===
 echo
 
-_make_test_img -ocompat=0.10 $size
+_make_test_img -o compat=0.10 $size
 
 run_qemu -drive file="$TEST_IMG",format=qcow2,lazy-refcounts=on
 run_qemu -drive file="$TEST_IMG",format=qcow2,lazy-refcounts=off