Since we have many iPad2 3G owners who are jailbroken, I wanted to take the time to remind everyone of the issues we face regarding jailbreaking on the iPad2 3G…
On 12th October, Apple will release IOS5 to the public and shortly afterwards, usually within 48 hours, they will stop signing IOS 4.3.5 for the iPad.
When Apple stops signing 4.3.5 you will no longer be able to restore your iPad2 3G to IOS 4.3.3 even if you have saved SHSH Blobs
The reason for this is related to the 3G modem firmware, also known as the baseband. IOS 4.3.3, 4.3.4, and 4.3.5 all share the same baseband version, namely 04.10.01. IOS5 ships with baseband 04.11.08. Basebands need signatures from Apple just like firmwares, but they cannot be saved and reused like firmware SHSH Blobs.
Up till now if you restored 4.3.3 with saved blobs the process would succeed because the installation of the 04.10.01 baseband also succeeds, since it is the current baseband for 4.3.5 which Apple is still signing.
However, once the new baseband is released you will not be able to successfully complete a restore to 4.3.3 with blobs because the installation of the 04.10.01 baseband in 4.3.3 will fail. Because we do not have a bootrom exploit for the iPad2 A5 chip yet, we can't pwn this process and correct it like we can with the iPad1 3G or iPhone4. Therefore, a failed baseband install equals a failed IOS restore. You will simply end up in a restore loop which can only be fixed by restoring to the latest version of IOS, which will be 5.0.
So, from October 12th onwards, iPad2 3G owners will need to be very careful! If anything goes wrong with your device which necessitates a restore, you will lose you jailbreak because you will be forced to restore to 5.x. There will be no way round this. You have been warned!
Of course on the bright side we know up to 5 userland exploits have been identified for IOS5 by the Chronic Dev Team. However, you may still have to wait a while for one of these to be developed into a working jailbreak, then tested and released to the public.
Please note, none of this applies to iPad1 owners or those with the iPad2 WiFi Only model. If you have saved blobs you will always be able to restore back to a 4.x firmware if you need to.