diff --git a/nixos-infect b/nixos-infect
index 8b4f33b..06f0171 100644
--- a/nixos-infect
+++ b/nixos-infect
@@ -325,8 +325,8 @@ infect() {
   # TODO use addgroup and adduser as fallbacks
   #addgroup nixbld -g 30000 || true
   #for i in {1..10}; do adduser -DH -G nixbld nixbld$i || true; done
-
-  curl -L https://nixos.org/nix/install | sh -s -- --no-channel-add
+  NIX_INSTALL_URL="${NIX_INSTALL_URL:-https://nixos.org/nix/install}"
+  curl -L "${NIX_INSTALL_URL}" | sh -s -- --no-channel-add
 
   # shellcheck disable=SC1090
   source ~/.nix-profile/etc/profile.d/nix.sh