iPhone 4 JB Monte - will I lose my unlock?

[pentatonic145]

Hi folks,

I'm a registered dev with legit access to the 4.2b3 IPSW. My iPhone 4 is currently jailbroken on 4.0.1 with BB 01.59.00 unlocked with Ultrasn0w. I have my SHSH blobs for 4.2b3 in Cydia and TU.

Before I pull the trigger on JB Monte to get to untethered, jailbroken 4.2.1, I have some questions:

*Will my BB update in the process, thereby costing me my unlock?
*What known issues am I risking? It sounds like the BT problem is fixed, but what about GSM and GPS issues?
*What version of Redsn0w should I use? There's so many out there - it's kind of confusing...

Thanks for helping. Sorry if this info appears elsewhere - I tried scrubbing the forums but couldn't find answers to the above.

-Bobby

[Simon]

You can do this but it will be a bit tricky.
You will need redsnow 0.9.7b6 and tiny umbrella, as well as the 4.2b3 firmware.

To get to 4.2.1 you will need to update (not restore, has to be update). Make sure tiny umbrella tss server is running and you are getting no errors. During the update you will get an error, just use tiny umbrella to exit recovery when you do. Once booted up activate with a official carrier sim if you have one, then you can do the untether jailbreak with redsnow.

This is a little risky to do just so that you know what you are getting into.

[pentatonic145]

Brilliant! I'll be attempting this today and I'll report back.

Thanks!

BTW - Currently my hosts file points to Saurik's server - should I remove that line? Will having it in there interfere with TU?

BTW BTW - I am using a MBP running Snow Leopard with iTunes 10.1.1

Thanks again

[Simon]

Leave that line in there. Whatever you do make sure you do not point your hosts to Apple. That is the only way your baseband will get updated.

[pentatonic145]

Just to be clear, is this the correct update procedure? :
*Connect to iTunes with TU TSS server running
*In iTune, do an Option-click of "Update" button
*Point to my 4.2b3 IPSW
*Update

?

Thanks!

[Simon]

No, you don't want to update to 4.2b3. You have to update to 4.2.1. I will list the steps for you in a few minutes.

[pentatonic145]

"This iPhone could not be updated - Error 21" - This error occurs before iTunes actually flashes 4.2.1 and when I kick it out of recovery mode with TU and it boots up again, it's still on 4.0.1 :-(

I've tried putting it into recovery mode and DFU mode, but then the option to "Update" in iTunes becomes grayed out and it will only let me "Restore", which I don't want to do.

I still have a fully-functioning iPhone 4 Jailbroken on 4.0.1 unlocked on 01.59.00 but I'd love to update to 4.2.1 if possible. Can someone help me get past this Error 21?

[Simon]

tbh I would say hold off for now. It is just too risky, too many things can go wrong. Wait for a updated pwnage tool to come out that makes untethered custim 4.2.1. That is the safest way to do it.