Haven't tried this, but have many reasons to think it works. This is based on the new BL5.8 exploit by geohot.

PHaseBanDowngrader - The iPhone Wiki

-------------- EDIT -----------------

If you haven't been able to with the above link, try the link below:
http://iclarified.com/entry/index.php?enid=3583

Will it work with booloader 6.02?
Didnt heard anything about this one.

Thanks

ther is no bootloader 6.02 or at least as far as we know.
there is only 5.8 and 5.9

__________________
Iphone 3gs 16gb(Black) Fw 3.1.2
Unlocked/Jailbroken with Blacksn0w

Call In/Out - Yes/Yes
SMS In/Out - Yes/Yes
EDGE/WIFI - Yes/Yes
YouTube - Yes
Jailbreak-Yes

I have a 3g phone bought in july. how do I know if my bootloader is 5.8? I have the 2.30.03 baseband along with 2.2.1 firmware.

would love this to be true, hoping to buy one this week

Hi..
I have some iphones for sale and I was checking the bootloader version and I have 2 iphones w bootloader 06.02

I did not find anyone w 05.08 bootloader, so i guess wait for another solution..

Install Minicom from Cydia, then follow these instructions...

1. After installing Minicom from Cydia, make sure the folder /usr/etc exists. SSH into your iPhone and then, type: minicom -s
2. Now, select Serial Port Setup in the Menu and press Enter. Then, press "a" and set Serial Device to /dev/tty.debug. press enter.
3. Press Esc, and in the Main Menu, select Save setup as dfl. Now, select "exit".
4. To run minicom using ssh, just run minicom -w
5. To get the bb version type at+xgendata

Anyone want to try this? I'm scared to do it on my phone. And I tried to find out what bootloader I have and have not been success. I installed minicom but I dont see the usr/ect folder when i ssh in

I have installed minicom and have succesfully checked my bootloader only to find out that it's 5.9 instead of 5.8.
could someone explain when it got updated to 5.9 from 5.8? is this something that comes along with firmware 2.2.1? or where does the change occur? what updated it to this latest version?
I last restored to 2.2.1 on the 17th of march this year.
Help?

what bootloader does 3.0 have? can we upgrade to 3.0 and then downgrade the firmware to an earlier version that would have the 5.8 bootloader?