diff --git a/Mf-stex b/Mf-stex
index 09ec6f3..11fb214 100644
--- a/Mf-stex
+++ b/Mf-stex
@@ -112,9 +112,11 @@ $(x).mathrun: gifs $(mathfiles)
 
 gifs:
 	(cd $(STEXLIB); tar -cf - gifs) | tar -xpf -
+	chmod u+w gifs
 
 math:
 	(cd $(STEXLIB); tar -cf - math) | tar -xpf -
+	chmod u+w math
 
 $(mathfiles): $(x).hthirdrun $(figps)
 	echo -n gifs= > $(mathfiles)