Thank you, if there is anyone here who is interested I want to share my information
I finally got rgh modded console and modifying the game is much easier because the game works with extracted big archives. Just extract big file and move folders in the games root folder and then remove extracted big file. For example modding rendering textures extract nocacherender.big and cacherender.big to same folder and copy the folder in the games root folder. Then move nocacherender.big and cacherender.big away from the root folder. There is a list of all the files inside the archives in attachment.
I'm trying to find a way to mod the files for retail consoles but I have not succeeded. I installed the game from disc to hard drive and then try to replace modded file in data0000, data0001, data0002… files with hex editor. I found the chunklzx compressed rx2 files in data000x but when replacing it and injecting data000x files back to xbox 360 hard drive game crashed. I’m sure that the files are signed by Microsoft so if trying to modify anything data will be corrupted. So sad for retail owners
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