That's what I've done. Using CID53 flash files (FS and MAIN) and FAR Manager says it is all successful, including putting the language customize.xml file in. I've tried all combinations of the FS, MAIN and all the customize.xml files. All goes on successfully according to Far Manager, it's just when I turn it on, it says "inactive sim" or "emergency calls only" yet I can use it for everything else- camera, music, storage. Just not for use as a PHONE (ringing, texting!). Maybe there's a setting in the EROM for allowed network bands, and as it's CID53 I can't do anything about it (I DO have a backup of the EROM from when it was a CID52, I just can't restore it as you can't change EROM on a CID53 yet!).