: Some custom patches include a "force unlock" feature that grants access to the full gallery and sound test without requiring multiple playthroughs, which is achieved by patching the game's executable (XEX) file. Technical Implementation

To understand the underlying environment you are developing for, this video explains how JTAG/RGH mods allow for this kind of custom feature implementation:

Feature development on JTAG/RGH usually requires to decompress and edit the game's executable and Le Fluffie or Xbox Backup Creator to modify the game's container files.