Iphone 4, IOS 5.1 Baseband 04.12.01 -- Bad luck.. your iphone is now just an ipod.. wait for dev team to come up with a solution.
If you have an iphone 4 which by mistake upgraded to IOS 5.1 through iTunes updates then you are unlucky. Check its baseband ( Settings > General > Modem Firmware ). If it is 04.12.01 there is no going back. No tools available can downgrade the baseband. You may downgrade the ios version but not the baseband. If you have saved the shsh blob files before updating to ios 5.1 then you may be lucky.
You can downgrade from 04.12.01 to older only if you have saved the shsh blob files.
If you have saved them then click here for the procedure.
Apple unsigned ios 5.0.1
so cannot downgrade from apple.
Unlock for basebands other then 04.12.01
http://jailbreakhow.net/unlock-iphone-4-3gs-on-ios-5.1-using-ultrasn0w-fixer/
And these are the tools usually used for to jailbreak ( use iphone for net, app store and itunes) and unlock (unlock from a sim like AT&T or Vodafone) iphone.
The team who works on iphone hacking is dev team. http://blog.iphone-dev.org/
Redsn0w
Ultrasn0w
sn0wbreeze
Notes:
You can't download a normal IPSW ( iphone software ) from any third party site and install it on iphone.
If you have an iphone 4 which by mistake upgraded to IOS 5.1 through iTunes updates then you are unlucky. Check its baseband ( Settings > General > Modem Firmware ). If it is 04.12.01 there is no going back. No tools available can downgrade the baseband. You may downgrade the ios version but not the baseband. If you have saved the shsh blob files before updating to ios 5.1 then you may be lucky.
You can downgrade from 04.12.01 to older only if you have saved the shsh blob files.
If you have saved them then click here for the procedure.
Apple unsigned ios 5.0.1
so cannot downgrade from apple.
Unlock for basebands other then 04.12.01
http://jailbreakhow.net/unlock-iphone-4-3gs-on-ios-5.1-using-ultrasn0w-fixer/
And these are the tools usually used for to jailbreak ( use iphone for net, app store and itunes) and unlock (unlock from a sim like AT&T or Vodafone) iphone.
The team who works on iphone hacking is dev team. http://blog.iphone-dev.org/
Redsn0w
Ultrasn0w
sn0wbreeze
Notes:
You can't download a normal IPSW ( iphone software ) from any third party site and install it on iphone.
