diff --git a/Makefile b/Makefile
index dce31b840b0..07208812edd 100644
--- a/Makefile
+++ b/Makefile
@@ -462,7 +462,7 @@ proto-update-deps:
 
 ## insert go package option into proofs.proto file
 ## Issue link: https://github.com/confio/ics23/issues/32
-	@sed -i '4ioption go_package = "github.com/confio/ics23/go";' $(CONFIO_TYPES)/proofs.proto
+	@perl -lp -i -e 'print q(option go_package = "github.com/confio/ics23/go";) if $$. == 4' $(CONFIO_TYPES)/proofs.proto
 
 .PHONY: proto-all proto-gen proto-gen-any proto-swagger-gen proto-format proto-lint proto-check-breaking proto-update-deps