Noobie Questions about iPhone 4 - Trying to go to t-mobile with regular 03.10.01

[Scmed27]

Greetings,

I haven't played with unlocking or even iPhone's since the 3G's... So I skipped over the 3GS and moved to the iPhone 4. I made the switch to T-Mobile today, getting myself on the non-contract Minutes/Texting Plan, which in turn they gave me a LARGE Sim Card... Now that i've purchased my iPhone 4, I see the first issue is my SIM Card. I am going to see if they will give me a micro sim tomorrow if not just cut it myself with a template. So this is not really an issue,... Moving on...

The iPhone 4 I just purchased is at the following stages, with me having done nothing to it:

Version: 4.2.1 (8C148)
Modem Firmware: 03.10.01

I am looking to upgrade "IF POSSIBLE" and then Jailbreak and then Unlock...

Before I get started, not having done this for a while and knowing the Version/Firmware I just threw out there... Is there anything I should be aware of in this process? Is there a certain firmware I should upgrade to before jailbreaking/unlocking? Any problems I should be aware of with not having a data plan at all?

Thanks for your help, it's greatly appreciated!

[i.Annie]

Can't unlock it right now. Maybe later on in a few weeks or months.

And you can't update it. That's the latest fw and bb version.

[Scmed27]

Have you heard of anyone downgrading these fw's or bb's? Or is it a lost cause at the moment?

for someone like me anyhow :P

[i.Annie]

The baseband is what determines unlocking. You can't downgrade it.

Downgrading the firmware doesn't downgrade the bb. Even if you wanted to downgrade the firmware, which there isn't a reason to at this point, you'd need SHSHs saved to do so.

If you weren't able to save SHSHs for 4.1 before it stopped being signed which was some time late last year, you won't be able to get them now.

[Scmed27]

Nooo! That sucks Should have done the research before buying the iPhone... Lesson to me.

Thanks for your help.

Has there been any hints of when 4.3 ipsw will be released? Or does that feed off of maybe weeks or months