diff --git a/nixos-infect b/nixos-infect
index a5c2a89..b111950 100755
--- a/nixos-infect
+++ b/nixos-infect
@@ -282,6 +282,7 @@ infect() {
   fi
 
   # this is needed solely for accpeting the sp-module subflake
+  # see https://github.com/NixOS/nix/issues/3978#issuecomment-952418478
   /root/.nix-profile/bin/nix flake lock ${LOCAL_FLAKE_DIR} \
   --extra-experimental-features "nix-command flakes" \
   --update-input sp-modules