diff --git a/Makefile b/Makefile
index 9c3f0b5209462866fc2605853f62e54fd12fc7d9..b92875bbd7de594fce006381f0876f5c7e668789 100644
--- a/Makefile
+++ b/Makefile
@@ -612,7 +612,7 @@ config_clean:
 	vboxmanage convertfromraw --format vmdk "$<" "$@"
 
 %.sha1sum : %
-	sha1sum "$<" > "$@"
+	(cd "$$(dirname "$<")" && sha1sum "$$(basename "$<")") > "$@"
 
 help:
 	@echo "Defaul Architecture: $(ARCH) ($(call altarch,$(ARCH)))"