Info - If want to use CodeUnique, I strongly suggest that you stay on 3.55 CFW.
I don't plan to go to Rogero 4.21 CFW at the moment. Unless there is a way to downgrade to 3.55 easily. I saw a post that a user have manage to downgrade to 3.55 by using the special downgreader pup. Waiting for more confirmation.
I think, CodeUnique can be resign with 4.21 keys. I believe oct0xor might release a update soon.
Maybe. If the Eboot values are not change except for the keys, the cheats might work.
might provide some information.