diff --git a/README.md b/README.md
index ba9b114..a2aa55e 100644
--- a/README.md
+++ b/README.md
@@ -3,5 +3,7 @@
 ```bash
 sudo nix run github:jeffguorg/nixos-kexec-profile
 # or boot it
-sudo nix run github:jeffguorg/nixos-kexec-profile -b
+sudo nix run github:jeffguorg/nixos-kexec-profile -- -b
+# or specify a nixos-config and boot it, either with a configuration.nix or flake.nix
+sudo nix run github:jeffguorg/nixos-kexec-profile -- -b /workspace/nixos
 ```