How to upgrade iPhone to iOS 6.1.2 preserve the baseband with redsnow.

Get the latest Redsn0w Windows

1)Launch redsn0w – click Extras
2) Select ‘Even More’
3) Select ‘Restore’
4) Select ‘IPSW’ 6.1.2
6) Select ‘Yes‘ to preserve your baseband
7) Get your device connected and in DFU Mode
8 ) with the device connected and turned off – when you click next you go through the DFU mode process
9)redsn0w will prepare a restore image and restore to your device maintaining your baseband and verify the restore
10) Success and an iPhone restart

Now your iPhone has iOS6.1.2 with a preserved baseband – now to Activate from iTunes.