You don't need to resign old 3.55 games. You only need to resign games that you had patched for 3.55 (games requiring FW 3.56 or higher) or restore their original eboots. Older games (requiring FW 3.55 or lower) that haven't been patched for 3.55 don't need to be resigned to run on 4.30 CFW.
I have rebug 4.21 REX edition that first came out months ago I just realized that an update to it was release back in January. So I was wondering do I have to downgrade to OFW 3.55 again in order to update to the 4.21.2 ? or can I just update my ps3 firmware over the Rebug 4.21 that I already have ?
I didnt do the QA flaged because when I first read about it was for ppl that downgraded their console and I knew mine never was downgraded and for some reason I couldn't get the QA flaged to work back when i had 3.55 CFW