diff --git a/t/t3800-mktag.sh b/t/t3800-mktag.sh
index dd21a1247a..e1a2892f58 100755
--- a/t/t3800-mktag.sh
+++ b/t/t3800-mktag.sh
@@ -41,7 +41,7 @@ check_verify_failure 'Tag object length check' \
 #  2. object line label check
 
 cat >tag.sig <<EOF
-xxxxxx 139e9b33986b1c2670fff52c5067603117b3e895
+xxxxxx $head
 type tag
 tag mytag
 tagger . <> 0 +0000
@@ -51,10 +51,10 @@ EOF
 check_verify_failure '"object" line label check' '^error: char0: .*"object "$'
 
 ############################################################
-#  3. object line SHA1 check
+#  3. object line hash check
 
 cat >tag.sig <<EOF
-object zz9e9b33986b1c2670fff52c5067603117b3e895
+object $(echo $head | tr 0-9a-f z)
 type tag
 tag mytag
 tagger . <> 0 +0000