A few tens of minutes ago, those from the Dev Team launched a new version of redsn0w that brings: the possibility to restore our iDevices to iOS 5.x, if we have the correct SHSHs available in Cydia or on the computer, it brings Cydia to all those who can jailbreak to iOS 6, untethered jailbreak for iPhone 3GS (with old bootrom) on iOS 6, hacktivation for iPhone 3GS and iPhone 4, a simpler restore method for iDevices released before iPhone 4, a new method to retrieve blobs from Cydia, the possibility to block the baseband update for iPhone 3GS or iPhone 4, the possibility to deactivate an iPhone, new information about the activation status, tethered jailbreak for Apple TV 2G, automatic saving of blobs in the computer, etc.:
- restore from Any 5.x iOS to any other (up, down or the same) 5.x iOS on all devices as long as you have the correct blobs (see more below)
- Cydia now included in the tethered 6.0 jailbreak on A4 devices
- automatically "Just Boot" tethered when qualifying A4 device connects in DFU mode
- untethered 6.0 jailbreak on old-bootrom 3GS
- untethered 6.0 hactivation on any 3GS or iPhone4
- directly restore pre-A5 devices to earlier firmware — no more complicated 15-step how-to's with stitching, iTunes errors, and "hosts file" concerns
- fetch new signed blobs for any IPSW (present or future — no redsn0w update required) using Extracts->SHSH Blobs->New
- block the BB update for any 3GS or iPhone4 restore (past, present, or future — no redsn0w update required) using Extract->Even More->Restore
- deactivate any iPhone, useful for testing your "official" unlock status through iTunes. (Please only deactivate your own iPhone!)
- activation status shown on "Even more" page
- significantly more (very nerdy) info returned by "Identify" button when device is in Normal mode
- tethered jailbreak of ATV2 supported (but the only thing available for it is the SSH2 custom bundle available here — no Cydia yet. Must use "Select IPSW" for tethered boot of ATV2 for now).
- auto-exit WTF mode for older devices with broken buttons
- any time a set of blobs is fetched remotely (from Apple or Cydia), redsn0w also saves them locally (and will check there first if you click "Local")
- for your future restoring convenience, you should also submit all of your past and present TinyUmbrella blobs to Cydia if you haven't done so yet. Resubmitting is okay and won't cause conflicts.
Apart from this long list of news, the Dev Team also explained the procedure by which you can restore to iOS 5.x if you have an iDevice released after iPhone 4, but this procedure does not allow you to downgrade from iOS 6 to iOS 5 for the same devices. I will talk about the rest0re procedure in a separate article, it is complicated, but you have described it on the Dev Team blog, so you can look it up there. Before updating to iOS 6, you must remember that ultrasn0w is not compatible with it for the time being and you may not be able to decode your terminals. redsn0w 0.9.15 beta 1 can be downloaded available here.
UPDATE: Here you are under what conditions can you restore to iOS 5.x or downgrade from iOS 6.
UPDATE 2 : Here you are how can you update to iOS 6 without updating the baseband.
UPDATE 3: Here you are how you can jailbreak and hack for iPhone 3GS and iPhone 4 on iOS 6.
