About to Jailbreak/Unlock a 3G iPhone 4.2.1. Do I have everything I need?

[MinimusMaximus]

I've been out of the loop a while since JB/Unlocking my 2G iPhone so I'm a bit overwhelmed by the tools available for the newer firmware.

I just got a used 3G iPhone with firmware 4.2.1 installed. A while back I remember the 4.2.1 fw could not be unteathered jailbroken, but now it appears it can.

I'm about to use this YouTube video instruction found on the redmondpie site. Can someone confirm that this guide is valid?
I'm running Windows 7 so basically the guide has you use Snowbreeze to jailbreak and recommends to select "Activate iPhone" if you plan on unlocking later; which I will since I'm on T-mobile.

So just to verify, after running Snowbreeze I install Ultrasnow which will allow me to unlock the phone correct?
Are there any other steps I'm missing or should be aware of?
Or better yet is there better JB/Unlock tools available or is Snowbreeze the way to go right now?

Also can someone tell me what exactly Snowbreeze does? It appears to create it's own 'custom' firmware, but once installed will it have things like Cydia already installed?

Thanks

[i.Annie]

Unlocking requires you to update the baseband to the iPad baseband, which will break your GPS. When restoring on 4.2.1 you would also only be able to use custom firmware from then on. If you are willing to accept those conditions, this is all you have to do:

1) get redsn0w 0.9.6rc19
2) get stock 4.2.1 ipsw
3) run redsn0w and select the 4.2.1 ipsw
4) select to install Cydia and the iPad baseband
5) continue on to follow the instruction to DFU
6) once finished you can access Cydia on your springboard
7) install Ultrasn0w from Cydia after doing the essential upgrades

There is no need for sn0wbreeze or custom firmwares for you at this point.

Edit: I was assuming you are on stock 4.2.1 so you would have the bb of 5.14.xx. Check that out before you do these steps. Also use f0recast and see what bootloader you have. With bootloader 5.8 you can downgrade the baseband instead of having to upgrade it. It's a slim chance to have the 5.8 bl but hey why not check just to be sure

If you do have the 5.8 bl let me know and I can help you to downgrade the bb. If you have 5.9 or 6.4 then my above steps are indeed the only option.

[xtacy]

One more thing your phone will run 3.1.3 much better then 4.2.1 :-)

[MinimusMaximus]

Unlocking requires you to update the baseband to the iPad baseband, which will break your GPS.

Is this because when the fw got updated to 4.2.1 the baseband was also updated with a version Apple tried to make un-unlockable?

When restoring on 4.2.1 you would also only be able to use custom firmware from then on.

What if I downgraded to 3.1.3 as xtacy suggests? will I still only be able to use custom firmwares... regardless of version?

One more thing your phone will run 3.1.3 much better then 4.2.1 :-)

So should I downgrade to 3.1.3 from 4.2.1? Does this involve anything more than acquiring the older firmware and selecting the 3.1.3 from Redsn0w when prompted?

Also, I forgot to ask about Whited00r. I'm looking into turning my old 2G (first gen) iPhone into a dedicated iPod for my car. Currently it crashes about once every couple days and I think it may be due to all the stuff I've installed over the course of owning it (jailbroken, unlocked, custom skins, etc).
If Whited00r is optimized to run better on older phones is that a better way to go? Including for the 3G

[Mes]

...If Whited00r is optimized to run better on older phones is that a better way to go???

If reliability and stability are important, stay away. Use jailbreaking and unlocking tools/utilities from well-known and respected sites. Dev-Team Blog