diff --git a/Makefile b/Makefile
index c386071..0328737 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-VERSION		= 12
+VERSION		= 13
 ifneq ($(origin RELEASE),undefined)
 DASHRELEASE	?= -$(RELEASE)
 else
@@ -171,7 +171,7 @@ shim.cer: shim.crt
 
 .NOTPARALLEL: shim_cert.h
 shim_cert.h: shim.cer
-	echo "static UINT8 shim_cert[] = {" > $@
+	echo "static UINT8 shim_cert[] __attribute__((__unused__)) = {" > $@
 	$(HEXDUMP) -v -e '1/1 "0x%02x, "' $< >> $@
 	echo "};" >> $@
 
@@ -337,7 +337,7 @@ clean:
 	$(MAKE) -C Cryptlib/OpenSSL -f $(TOPDIR)/Cryptlib/OpenSSL/Makefile clean
 	$(MAKE) -C lib -f $(TOPDIR)/lib/Makefile clean
 	rm -rf $(TARGET) $(OBJS) $(MOK_OBJS) $(FALLBACK_OBJS) $(KEYS) certdb $(BOOTCSVNAME)
-	rm -f *.debug *.so *.efi *.efi.* *.tar.* version.c
+	rm -f *.debug *.so *.efi *.efi.* *.tar.* version.c buildid
 
 GITTAG = $(VERSION)
 
diff --git a/buildid.c b/buildid.c
index b27aa1f..f213f3b 100644
--- a/buildid.c
+++ b/buildid.c
@@ -113,6 +113,7 @@ static void handle_one(char *f)
 	char *b = NULL;
 	size_t sz;
 	uint8_t *data;
+	ssize_t written;
 
 	if (!strcmp(f, "-")) {
 		fd = STDIN_FILENO;
@@ -132,10 +133,14 @@ static void handle_one(char *f)
 		b = alloca(sz * 2 + 1);
 		data2hex(data, sz, b);
 		if (b) {
-			write(1, f, strlen(f));
-			write(1, " ", 1);
-			write(1, b, strlen(b));
-			write(1, "\n", 1);
+			written = write(1, f, strlen(f));
+			if (written < 0)
+				errx(1, "Error writing build id");
+			written = write(1, " ", 1);
+			written = write(1, b, strlen(b));
+			if (written < 0)
+				errx(1, "Error writing build id");
+			written = write(1, "\n", 1);
 		}
 	}
 	elf_end(elf);
diff --git a/commit b/commit
index 14a907c..fc0d353 100644
--- a/commit
+++ b/commit
@@ -1 +1 @@
-23ce039c434d164a3848c829b237899cc17c1d21
\ No newline at end of file
+5e827007b3d95c4ce999422462248f5e7d3f270f
\ No newline at end of file