Index: boot/arch/sparc64/Makefile.inc
===================================================================
--- boot/arch/sparc64/Makefile.inc	(revision 29f8f8e3b2dd5fbe47f0fd28045b5a4c79c6d15f)
+++ boot/arch/sparc64/Makefile.inc	(revision af863d0df32b98f1005d2470e2de1d3e71a445e6)
@@ -37,5 +37,5 @@
 	cp arch/$(ARCH)/silo/README arch/$(ARCH)/silo/COPYING arch/$(ARCH)/silo/silo.conf $(TMP)/boot
 	cp arch/$(ARCH)/loader/image.boot $(TMP)/HelenOS/image.boot
-	gzip $(TMP)/HelenOS/image.boot
+	gzip -f $(TMP)/HelenOS/image.boot
 	mkisofs -f -G $(TMP)/boot/isofs.b -B ... -r -o $(BASE)/image.iso $(TMP)/