Updating iPhone 4 iOS 4.1 to untethered jailbreak w/ unlock without updating baseband
What I have now:
I have an iPhone 4 on iOS 4.1 with modem firmware 02.10.04.
It's jailbroken with GreenPois0n, and I have SHSH blobs for only iOS 4.2.1.
My goal is to update to iOS 4.2.1 (untethered jailbreak and unlocked).
(My phone was activated through an official carrier.)
There's a lot of information all over the web on how to do bits and pieces of this, so I'm trying to confirm if this is the correct procedure for my situation:
1. iClarified - iPhone - How to Jailbreak Your iPhone 4 Using PwnageTool (Mac) [4.2.1]
(At step 6, I should deselect "Activate" since my iPhone's legitimately activated on an official carrier, in order to prevent breaking push notifications too.)
I assume this is for untethered despite only being explicitly mentioned in a separate article here: iClarified - Apple News - PwnageTool 4.2 With iOS 4.2.1 Untethered Jailbreak Released! ?
2. At step 10 in the first tutorial, where we're about to restore from a custom .ipsw built with PwnageTool 4.2 in iTunes, I should switch to this tutorial:
iClarified - iPhone - How to Update Your iPhone 4 Without Upgrading the Baseband (Mac) [4.2.1]
and continue with the TinyUmbrella steps and...
3. ...ultimately, Greenpois0n, as step 9 in the last link suggests. So that leads me here:
iClarified - iPhone - How to Jailbreak Your iPhone 3GS, iPhone 4 Using Greenpois0n (Mac) [4.2.1]
4. Now that I'm jailbroken untethered (with an unchanged baseband?), I can unlock using Ultrasn0w here:
iClarified - iPhone - How to Unlock the iPhone 4, 3GS, 3G Using UltraSn0w, though it concerns me that my baseband of 02.10.04 isn't listed among their list of: 04.26.08, 05.11.07, 05.12.01, 05.13.04, 06.15.00, or 01.59.
Does this sound correct? The first three steps are for jailbreaking untethered with a custom IPSW for iOS 4.2.1 without updating the baseband. The fourth step is for unlocking on that original 02.10.04 baseband. Am I overcomplicating this?
Edit: I only suggest staying on my current baseband because of all the warnings against allowing the baseband to be updated to 06.15.00 or whichever comes with 4.2.1.