diff fc55d674565f65401a9fc89c90a3769d7c8cb4ae uncommitted
--- a//rc/bin/sysupdate
+++ b//rc/bin/sysupdate
@@ -5,4 +5,7 @@
 cd /
 if(! test -d .git)
 	bind -ac /dist/plan9front /
-git/pull -u gits://git.9front.org/plan9front/plan9front
+if(! ~ `{git/branch} heads/front)
+	>[1=2] echo sysupdate: must be on "front" branch to pull
+if not
+	git/pull -u gits://git.9front.org/plan9front/plan9front