iOS 4.2.1 Recovery Mode Exit Not Supported By TinyUmbrella!
For all those who have been eagerly waiting for iOS 4.2.1, we have some important piece of news to share. notcom, the guy behind TinyUmbrella, a tool which lets you save SHSH blobs both locally as well as on Cydia servers, has warned about an ensuing problem related to iOS 4.2.1 update.
According to notcom, TinyUmbrella cannot kick you out of recovery mode because of a baseband version requirement cleverly put by Apple in iOS 4.2.1. See his tweet.
Don’t update to 4.2.1. TU cannot kick you out of the ensuing recovery mode. Apple was cute and put a BB ver requirement on the firmware.
He also goes on to add this in another tweet:
The new BB requirement for firmware is a startling revelation. This has implications reaching beyond just folks that need to unlock… =/
Which means not just unlockers but jailbreakers in general are going to be affected by this.
Redsn0w 0.9.6b4, released today by the iPhone Dev Team can jailbreak iOS 4.2.1 on iPhone 4, 3GS, 3G, iPod Touch 4G, 3G, 2G, and iPad. But only the older devices including iPhone 3GS (old bootrom), iPhone 3G, iPod Touch 2G (MC) can have an untethered jailbreak.
Rest all, your jailbreak is going to be tethered till Comex releases a patch. Which means each time you reboot your phone, you will have to boot it into a jailbroken state. See this article for iOS 4.2.1 jailbreak and unlock update.