Hello, which device did you update? the RG35xxH? You might just reflash the firmware. I suggest to use a system sd-card and a secon sd-card with all the games. Then you only will need to update one "small" sd-card and don't risk to loose all your roms/games.
Make sure you got the BIOs files . Any firmware even if its the stock or custom needs it. Also make sure the roms files are inside correct folder and extracted
