iPhone Dev team has provided the following details:
Because of geohot’s limera1n exploit, those with devices earlier than the iPad2 can test the 5.1 jailbreak waters if they really want to, using redsn0w 0.9.10b6. Here’s what you need to know:
- This is a *tethered* 5.1 jailbreak for non-A5 devices. You’ll need to use redsn0w to “Just Boot” your device every time it power cycles, otherwise jailbreak apps won’t work (neither will Safari).
- If you use ultrasn0w for your carrier unlock, be sure to use a custom IPSW to get to 5.1 first! Don’t ever restore to a stock Apple IPSW! Use redsn0w’s “Custom IPSW” button to create a NO_BB_* version of the 5.1 IPSW and restore to that instead of the stock one. (That option is available only to 3GS and iPhone4-GSM owners.) ultrasn0w itself will be updated for 5.1 in the next few days (same baseband support, not 5.1’s baseband).
- If you’re lucky enough to have an old-bootrom 3GS, this jailbreak is actually untethered (redsn0w will figure that part out automatically).
- While we were at it, we added @pod2g’s steaks4uce exploit to support MC models of the iPod touch 2G (whose last firmware was 4.2.1). So now redsn0w will auto-detect and jailbreak all versions of that older device.
- iBooks won’t work until a future update of redsn0w
Please note that Redsn0w 0.9.10b6 can only perform a tethered jailbreak on iPhone 4, iPhone 3GS, iPad 1 and 3rd-generation iPod touch, which means that you need to connect your iOS device to the computer on every reboot. So if you’ve jailbroken your iOS device running on iOS 5.0.1, you are better off avoiding the iOS 5.1 software update, which doesn’t include any major feature.
If you need help in jailbreak your iOS device on iOS 5.1 then checkout our detailed step-by-step guides:
iPhone Dev team hasn’t provided any update on the jailbreak for iPhone 4S and iPad 2 running iOS 5.1. We’ll let you know as soon as there’s any update so stay tuned at iPhone Hacks or join our Facebook Fan page or follow us on Twitter or add us on Google+ or subscribe to our RSS feed.
[via Dev Team's blog]