Hey all, Tried to upgrade my firmware to 4.2.1 today. For whatever reason, from the first iPhone to this one, all the updates seem to fail on my old desktop, so I have to do the full firmware restore, restore from a backup, and resync. I was prepped to do that, but not for what happened this time. Firmware upgrade failed, so I restored. Went to restore from backup and it failed b/c I ran out of HDD space. I cleaned off some stuff and tried again, failed again, same reason. I cleared off some more space, and went to try to restore my settings again, and found out that iTunes had made a new backup (of nothing, essentially -- the brand-new empty phone's settings) and overwrote the prior backup, at least in part. I was able to find "parts" of my backed up files in two folders. Specifically, I found the 3d0d7e5fb2ce288813306e4d4636395e047a3d28 SMS file. I can browse them with the iPhone Backup Tool so I know they're intact. But because I don't have a valid backup, I can't restore them. I've tried restoring from prior backups and just overwriting its SMS file with the more recent one, but I end up with an empty SMS app on the phone. This seems to be the checksum problem. I understand from other posts here -- http://forums.macrumors.com/showthread.php?t=844995 -- that my options are to somehow hack the manifest's checksum for the SMS file so that iTunes accepts it, or to jailbreak the phone, replace the file, and update the SQLite database manually. I am not just not sure which would be the easiest, and I'm not familiar with any of the options. Does anyone have any suggestions? Thanks in advance.