Posted 21 February 2013 - 22:46
You will need to do a "restore" firmware installation to upgrade to v6.1.2, restore your backup, and then apply Evasion.
I think that is the only "safe" way to update. It might be OK to just update w/o doing a restore, but I'm not sure about that. OTA incremental update is def. out of the question.
Seems like since iTunes 11 and iOS 6, all the backup/restore hickups are gone. I completed the process in about 45 minutes.
If you have a device that was made after the iPhone 4, there is currently NO WAY to restore old firmwares. The SHSH stitch method apparently does not work. This is being worked on, and I'm sure it will be a bigger deal once Apple "fixes" the jailbreak exploit. That being said, since 6.1.2 IS jailbreakable, it is probably a good idea to go ahead and update to it as soon as you can because when 6.2 (or w/e) comes out the opportunity will be lost.