I have a solution working with the 64 bit update (ultrawide monitor, 3440x1440, Steam version).
- Open the game executable (PG4.exe) in a hex-editor such as HxD. Use hexadecimal values.
- Search for 398EE33F and replace by 8EE31840 (1 ocurrence).
- Search for 0000F0440000FA44 and replace by 000021454000FA44 (1 ocurrence)
This removes black bars. FMV and HUD are streched, but Gameplay and other cinematics are fine.