diff --git a/tests/qemu-iotests/194 b/tests/qemu-iotests/194
index c0ce82dd25..d0b9c084f5 100755
--- a/tests/qemu-iotests/194
+++ b/tests/qemu-iotests/194
@@ -34,6 +34,7 @@ with iotests.FilePath('source.img') as source_img_path, \
 
     img_size = '1G'
     iotests.qemu_img_create('-f', iotests.imgfmt, source_img_path, img_size)
+    iotests.qemu_io('-f', iotests.imgfmt, '-c', 'write 512M 1M', source_img_path)
     iotests.qemu_img_create('-f', iotests.imgfmt, dest_img_path, img_size)
 
     iotests.log('Launching VMs...')