Permanently unlock TimeSplitters 2 easter egg inside Homefront: The Revolution using this file.
Download the file Timesplitters.ups
Navigate to https://www.marcrobledo.com/RomPatcher.js/
In ROM file, select Homefront2_Release.exe which is in the Bin64 folder, normally in Steam\steamapps\common\Homefront_The_Revolution\Bin64\
In Patch file, select Timesplitters.ups
Click Apply patch
Download the file (your browser may warn that this file isn't safe, download at your own discretion)
Paste the file into the previous \Bin64\ folder
Run the game
This patch permanently enables the codes to unlock:
All Story levels
Fixes the crashes caused by Reaper Splitters spawning in Return to Planet X, Wild West, Atom Smasher, Aztec Ruins, Robot Factory, and Space Station.
Many thanks to Fanoto for creating this file (uploaded with permission) from the HF:TR/TS2 Redux Egg Hunt Discord and this Steam guide by Yossarian the Assyrian.