This is where FitGirl enters the equation. FitGirl is the most famous name in game repacking. She does not crack games; she repacks existing scene releases (like CODEX) to minimize download size using custom compression algorithms (FreeArc, LZMA, etc.) and lossless repacking techniques.
The group CODEX—which ceased operations in 2022—was famous for bypassing Denuvo. For the Update 20191218, they did not release a full game ISO. Instead, they released a delta patch. RESIDENT EVIL 2 Remake Update 20191218 CODEX- FitGirl
A delta patch (usually a 300MB to 600MB archive) scans the original game files from the January 2019 release and rewrites only the bytes that changed. This is distinct from a "scene crack," which is just the .exe and .dll files. This is where FitGirl enters the equation
CODEX’s release notice (NFO) for this update specifically noted: "We have included the updated crack only
"We have included the updated crack only. You require the following releases: RESIDENT.EVIL.2-CODEX + Update v20191218 (this file). Use our .exe to unlock DX12 features."
If you found an old hard drive with the FitGirl repack of this update, here is how to handle it correctly: