Factorio achievements after cheats

We play a lot of Factorio on a multiplayer server.

Our first version of the map had pollution enabled. Eventually the biters made the game more annoying than fun, so we used a few console commands to calm them down. That disabled achievements.

This is how I edited the save to turn them back on.

1. Download the save file.
2. Make a backup.
3. Load the map locally, run the required /c commands, save, and exit.
4. Extract level.dat and open it in a hex editor.
5. Search for 6A D8 40.
6. Find the next FF FF FF FF FF FF FF FF 00 00 01 sequence after that match.
7. Change the final 01 to 00.
8. Put level.dat back into the save archive and confirm the change persisted.
9. Upload the save to the server.

This worked on Factorio 1.1, back in mid-2023, before the 2.0 / Space Age update. The byte sequence may be different on later versions, so check it against your own save before trusting it.