diff --git a/justfile b/justfile
index 28106a7..318e88d 100644
--- a/justfile
+++ b/justfile
@@ -52,7 +52,7 @@ vm hostname=(HOSTNAME):
   @nixfmt . &> nixos-switch.log || ( cat nixos-switch.log && false )
   @rm -f nixos-switch.log
   @echo Running iso build
-  @nixos-rebuild build-vm --flake .#{{hostname}}
+  @nixos-rebuild build-vm --impure --flake .#{{hostname}}
   export QEMU_NET_OPTS="hostfwd=tcp::2221-:22"
   result/bin/run-{{hostname}}-vm