What’s old is new again!

Jailbreakers with devices that pre-date the iPad2 will always be able to downgrade (with SHSH blobs) to previous firmware versions due to geohot’s limera1n exploit, which allows us to bypass the restrictions that Apple places on restores.  But until now, that ability has been limited to those older devices (if you have an older device and don’t know how to do that, check the popular tutorial sites or ask in the comments below).

Starting with redsn0w version 0.9.11b1, those with newer devices (iPad2, iPad3, and iPhone4S) can join the downgrade fun too!  In a radical departure from previous versions of redsn0w, it now directly supports restoring IPSWs to your device.  The first use of this new feature implements a hack that allows A5 downgrades without a bootrom-level exploit.

Some important points:

• The new feature is at Extras->Even More->Restore
• You cannot downgrade without the personalized SHSH blobs for your device at that lower firmware.  You need to have fetched those blobs while the signing window was open, using either Cydia’s built-in TSS@Home feature, or with TinyUmbrella.  The new Restore screen of redsn0w lets you choose either the remote blobs or local ones (for the earlier firmware).  If you don’t know where TinyUmbrella put your blobs, TinyUmbrella has a button that will show you (copy them out of that folder and feed them to redsn0w).
• The A5 downgrade method actually updates to the latest firmware before downgrading to the earlier one. This process updates your baseband to whatever is newest.  DO NOT USE THIS METHOD IF YOU RELY ON UNOFFICIAL UNLOCKS of your iPhone4S.  Those who used the temporary SAM technique to unlock their iPhones to specific SIMs shouldn’t be affected by this baseband update.
• This method can be fixed by Apple with a firmware update.  It’s a (pleasant) mystery why they haven’t fixed it yet, because reverse-engineering of the restore ramdisk indicates they do know about it.  It’s possibly too niche to bother to fix right now.
• The least-tested devices with this method are the iPad2,3 and iPad3,2 (because we don’t have those models).  If you do and you feel like experimenting, please let us know how it turns out in the comment section below!
• This update involves a bunch of new redsn0w code.  We recommend sticking to the previous version 0.9.10b8b unless you’re specifically using this new feature, until all the bugs are worked out!  (Note: If redsn0w gets stuck at the “Waiting for device” stage for more than 30 seconds, you’ve hit a pesky GUI bug…that will be fixed in an upcoming version!)

Of course all eyes are on @pod2g for his upcoming 5.1 untethered jailbreak.  Watch his blog or twitter feed for the latest updates about that, but in the meantime if you accidentally updated your jailbroken A5 device to something later than 5.0.1, feel free to try this new A5 firmware downgrade feature of redsn0w!

Update #1: We accidentally left out one of the two flavors (“9A406”) of 5.0.1 for iPhone4S.  It’ll be in the next update, but in the meantime check if Cydia or TU saved your blobs for the other 5.0.1 for iPhone4S (“9A405”). Version 0.9.11b2 adds support for that second “9A406” flavor of 5.0.1 for the iPhone4S.

Update #2: Version 0.9.11b3 should fix the spurious “Restore failed” messages people were sometimes getting, and it behaves better with nearby devices that have wifi syncing enabled!

Update #3: Version 0.9.11b4 completes the tethered JB support for 5.1.1 on A4 devices and earlier, including proper “Stitching” and “Custom” creation of NO_BB IPSWs.

Here are the redns0w download links:

• redsn0w 0.9.11b4 for OS X
• redsn0w 0.9.11b4 for Windows (be sure to run in Administrator mode)

Despite the awkward name Apple announced last week for the new iPad (we’ll continue to call it iPad3!), by all signs it’s going to be another big hit.  We suspect many of you are lined up at this very minute, and so it’s a good time to give you some info for maximizing your chance to eventually jailbreak the iPad3.

There are a few bits of good news already.

• We can confirm that the method used to jailbreak the iPad2 4 months ago (before corona) still works even in 5.1.  That means we’ll at least be able to get our foot in the door to get the required kernel dumps on the iPad3.  That’s an important step, but by no means is it the end of the story.
• Those of you following @i0n1c may have noticed he’s already tweeted pictures of his iPad2 jailbroken at 5.1.  As far as we know, he’s using a method completely unrelated to the one mentioned above.  That would be great news!
• We’ve also seen bits and pieces of an entirely different jailbreak method being investigated by someone close to the Cydia repo scene: @phoenixdev

That’s three different angles, and we’re not even including the continuous work @pod2g makes towards a new jailbreak!  As always, keep in mind this is very preliminary progress, and it’s impossible to predict how or when these things turn out.  The only thing you need to remember is the golden rule:

Don’t update your new iPad3 past whatever iOS it comes shipped with

By the way, it’s rare but entirely possible that some of you may find your iPad3 comes with an iOS version that’s not quite 5.1.  If you do, be sure to let us know in the comments below!

Update #1: It turns out that all three of the jailbreak methods mentioned above have had great success today!  We’re off to a good start (but remember there’s still lots of work to do)!

• Method 1 shown by @MuscleNerd
• Method 2 shown by @i0n1c
• Method 3 shown by @chpwn and @phoenixdev

As the whole tech world waits for today’s Apple Event, it seems like a good time to remind both veteran and amateur jailbreakers about the fundamental rule of jailbreaking:  Avoid firmware updates!

In all likelihood we’ll see the GM “gold master” version of 5.1 this week.  DO NOT UPDATE TO 5.1, because you may lose your jailbreak!  The rest of this post details the subtleties with this rule, but if there’s only one message to take home, it’s the overall “do not update” message!  Now for the nitty gritty exceptions:

• Soon after 5.1 appears on Apple’s public servers (i.e. iTunes starts to offer it), Apple will stop signing 5.0.1 SHSH blobs.
• If you have an iPhone4S, the basic rule above is really the only rule:  you cannot restore back to 5.0.1 once the 5.0.1 signing window is closed, no matter what (even if you saved your SHSH blobs).
• If you have an iPad2 with saved 4.x hashes, you can in fact downgrade to that 4.x but you won’t be able to get to 5.0.1 once the 5.0.1 signing window is closed (even if you saved your 5.0.1 SHSH blobs).
• If you have a device earlier than the iPad2, you can downgrade to whatever version you want, as long as you have saved SHSH blobs for that version.  You’ll need the assistance of geohot’s limera1n exploit with tools like redsn0w to get into “pwned DFU mode” and bypass the downgrade restriction.

As you can see, it really is a nuanced landscape so it’s sometimes hard to drive the message home to new jailbreakers.  But the basic rule is the simplest (and it’s better to be safe than sorry!):  If you update to 5.1 you’ll very likely lose your jailbreak, so don’t do it!  Exceptions are noted above.

Now let’s see what Apple unveils today!