diff --git a/rspy/Makefile b/rspy/Makefile
index a895af7b8..7215bf937 100644
--- a/rspy/Makefile
+++ b/rspy/Makefile
@@ -45,5 +45,6 @@ RUST_TOOLCHAIN := $(shell cat rust-toolchain)
 
 VER := $(shell cat ../meta/version)
 .build/vernum: ../meta/version
-	sed -i '' 's/.*automatically updated.*/version = "$(VER)" # automatically updated/' Cargo.toml
+	sed -i.bak 's/.*automatically updated.*/version = "$(VER)" # automatically updated/' Cargo.toml
+	rm Cargo.toml.bak
 	@touch $@