Unlocked iPhone 4 on 4.0.1, how can I update and keep baseband

[ann713]

My phone is jailbroken and unlocked on version 4.0.1. Baseband is still on 1.59.00. What is the highest OS version I can update/unlock to, while preserving the baseband (as of right now)? Is there a detailed guide out there to do so?

 

[Sine Qua Non]

4.3.2 just came out today. Do NOT update to it through iTunes. You will lose your JB and unlock.

There is an untethered JB for 4.3.1 for the iPhone 4. The iPhone 4 baseband on 4.3.1 is not unlockable. You can preserve your current unlockable BB and upgrade to 4.3.1 by creating and installing a customized 4.3.1 with PwnageTool. Check the tutorials on iclarified.com for complete instructions.

This all presumes that you can still save your SHSH for 4.3.1 despite 4.3.2's release today. Your first step should be to download TinyUmbrella IMMEDIATELY and try saving your SHSH.