Upgrade to 4.2.1 without upgrading baseband
I am very confused by the usually great iClarified tutorial on unlocking 4.2.1 with redsnow.
I have a 3G jailbroken and unlocked on 4.0.1. I only have windows available so can't easily make a custom ipsw.
I want to go to 4.2.1, BUT reading the tutorial suggesting a shift restore to 4.2.1 makes me believe that I will inadvertently upgrade baseband currently 05.13.04. If that is the case then I would have to go the iPad route to unlock, which I do not want.
Have I understood correctly or will redsnow preserve baseband at 05.13.04 because it doesn't seem obvious to me.
If I am being obtuse apologies but any help in giving me comfort that I can follow tutorial safely would be appreciated.
3G jb/unlocked 4.0.1