diff --git a/Makefile b/Makefile
index 2f94ef3..991ca00 100644
--- a/Makefile
+++ b/Makefile
@@ -100,7 +100,7 @@ sync-arch:
 # Firefox
 	-@$(RM) $(HOME)/.mozilla/firefox/*.default-release/user.js
 	@$(WGET) $(REPO_SRC)/.mozilla/firefox/user.js -P $(HOME)/.mozilla/firefox/*.default-release
-	@$(CURL) $(REPO_SRC)/.mozilla/firefox/user-arch.js >> $(HOME)/.mozilla/firefox/*.default-release/user.js
+	@$(CURL) $(REPO_SRC)/.mozilla/firefox/user-arch.js >> $(wildcard $(HOME)/.mozilla/firefox/*.default-release)/user.js
 
 # VSCodium
 	@$(WGET) $(REPO_SRC)/.config/VSCodium/product.json -O $(HOME)/.config/VSCodium/product.json