Works Fine.. Except your signal bars will always say 1 bar. doesn't effect performance.

Depends on the timezone... It is almost 9pm in California.....

Function REQ's -- To be able to preserve the baseband

1. Have redsnow remove the baseband check in 4.2.1

2. Instead of having it automatically hactivate a phone, make it an option, because itunes wont activate it if it still has the baseband check in it.

Step 2 can be removed if step 1 only removed the bootrom check, and not jailbreak, then you would activate it, and then JB the phone.

I was able to preserve my baseband and do a untethered JB.

Here is the long process

1. Get the custom bundle for pwnage tool. Use the newest pwnage tool. Install that to your phone.(Cant post URLS, so you will have to google "iphone 4 4.2.1 bundle". Should be the first hit. It will be on the blogsdna site.) Don't mess with it's tether boot process. It will boot just fine(Non JB apps), and it will retain your old baseband. After it is boots up, let itunes activate it (If you still have the original sim) Then turn off the phone.

2. get the latest untethered Redsn0w (I used beta 3, but beta 4 should be fine). Run it, and only select "Install Cydia". After it is done, turn off the phone.

3. Run redsnow again, and select "Tethered boot only". Then boot the phone, and load cydia. Do the complete updates, Let it reboot, then turn off the phone.

4. Run RedSn0w again, and only select the JB Monty option (Untethered JB)

5. Boot up your phone. You should be all good, and you can install Ultrasn0w for unlock if needed.

I ended up putting 4.1 back on, because of broken skype, Winterboard themes not working completely (a 4.2.1 issue, not a untethered issue.), and other littie glitches due to 4.2.1, not the untethered process.

It was a good test :)

Get rid of 4.0.1. Use pwnage tool, and create a custom 4.1 IPSW, Or install Tiny umbrella, and put 4.1 on your phone, and JB with redsnow, limera1n, or Greenp0ison.

Right now 4.1 is solid, and stable. I tried the 4.2.1 Untethered JB, and it workes, but there is still tons of JB apps that need to be updated to work right for 4.2.1. (Even did it preserving my baseband. not an easy feat)

in 3 months or less. Maybe longer...

I thought they started it at least at 3.1.2

I have the iPhone 4 since the first week.
I have these saved:
iPhone4 4.0 (8A293)
iPhone4 4.0.1 (8A306)
iPhone4 4.0.2 (8A400)
iPhone4 4.1 (8B117)
iPhone4 4.2.1 (8C148)
iPhone4 4.2b3 (8C5115c)

I have a Macbook 2.4 ghz. Snow Leopard, and all the latest updates.

I have 4.1 running right now. Did try 4.2.1, but tethered sucks. I still have the 01.59.00 Baseband.

Unlock isn't that important. Not leaving the country till march at the earliest.

Everyone is!!!! The iPad has a different GPS chip, so there is no REAL GPS with the 6.15.00 firmware!!!

The phones that have "Working" GPS, are just triangulations of cell towers, and WiFi signals.

Sure. There will most likely be a unlock out before your trip.

So Leave it alone, and don't sweat it till your trip. if there isn't an unlock by then, you will have to get the 6.15.00, or get a crappy phone to use over there.

IF you load Tiny Umbrella, and use ANY 3G it will save all the SHSH's from 4.0 to current. I even tried making up numbers to test it. like 3987654321000. I even did 3987654321001 and 3987654321002. Populated ALL of them!! So that means that with a 3G, you can put any Apple IPSW on it you want still.

Tried 3987654321003 as a iPhone 4, and it only got the SHSH for 4.2.1, so it looks like apple stopped signing 4.2b3