diff --git a/test/units/testsuite-50.sh b/test/units/testsuite-50.sh
index ab65c86ba8..8c4d2bfc3f 100755
--- a/test/units/testsuite-50.sh
+++ b/test/units/testsuite-50.sh
@@ -134,8 +134,8 @@ fi
 # Make a GPT disk on the fly, with the squashfs as partition 1 and the verity hash tree as partition 2
 #
 # du rounds up to block size, which is more helpful for partitioning
-root_size="$(du -k "$MINIMAL_IMAGE.raw" | cut -f1)"
-verity_size="$(du -k "$MINIMAL_IMAGE.verity" | cut -f1)"
+root_size="$(du --apparent-size -k "$MINIMAL_IMAGE.raw" | cut -f1)"
+verity_size="$(du --apparent-size -k "$MINIMAL_IMAGE.verity" | cut -f1)"
 signature_size=4
 # 4MB seems to be the minimum size blkid will accept, below that probing fails
 dd if=/dev/zero of="$MINIMAL_IMAGE.gpt" bs=512 count=$((8192+root_size*2+verity_size*2+signature_size*2))