diff --git a/xen/Makefile b/xen/Makefile
index ee8ce8e2a0..76b60bc6d4 100644
--- a/xen/Makefile
+++ b/xen/Makefile
@@ -121,7 +121,7 @@ _distclean: clean
 	rm -f tags TAGS cscope.files cscope.in.out cscope.out cscope.po.out GTAGS GPATH GRTAGS GSYMS .config
 
 $(TARGET).gz: $(TARGET)
-	gzip -f -9 < $< > $@.new
+	gzip -n -f -9 < $< > $@.new
 	mv $@.new $@
 
 $(TARGET): delete-unfresh-files
diff --git a/xen/arch/x86/boot/mkelf32.c b/xen/arch/x86/boot/mkelf32.c
index 6cfa312b1e..e66740fc16 100644
--- a/xen/arch/x86/boot/mkelf32.c
+++ b/xen/arch/x86/boot/mkelf32.c
@@ -260,7 +260,7 @@ int main(int argc, char **argv)
     u32        loadbase, dat_siz, mem_siz, note_base, note_sz, offset;
     char      *inimage, *outimage;
     int        infd, outfd;
-    char       buffer[1024];
+    char       buffer[1024] = {};
     int        bytes, todo, i = 1;
     int        num_phdrs = 1;