Downgrade your Desire/Bravo HBOOT from 1.02.0001 to 0.93.0001
This is how you downgrade a Desire/Bravo with the HBOOT 1.02.0001 already installed, - this method is appropriate for people who need to downgrade the HBOOT for unlock purposes. I struggled for ages on this and once I found the method thought i'd post it around the internet as I couldn't find this info anywhere.
-Summary of steps-
1)Turn S-Off + Update HBOOT
2)Downgrade HBOOT to 0.93.0001 (Turns S-ON)
I have personally tested this and it worked perfectly without any problems. However flashing anything to your phone is done at your own risk, & I accept no responsability for your device.
Download and run the Revolutionary tool here Revolutionary to turn S-Off - Follow the steps on their website for how to do this if you get stuck.
Once you have run the Revolutionary tool, when it asks if you want to install the Clockworkmod recovery press no.
You will now have an S-Off phone running HBOOT 6.93.1002
Format a microSD card, download the following zip file and save it to your memory card.
You should now have a single file on your memory card named PB99IMG.zip
Put the microSD card back in your phone and hold 'VOL+DOWN + ACTION' and press the power button to get to the HBOOT menu. Wait around 10 seconds (give or take) and the phone will detect the update and ask you to install it, Select yes to install then reboot your phone back into the HBOOT menu.
You will now have an S-On phone with the 0.93.0001 HBOOT
--Step4-- IF THIS STEP APPLIES TO YOU FOR UNLOCKING
Unlock with XTC-Clip as you normally would - Creating goldcard with 0.93.X001 HBOOT.
Your phone will now be unlocked.[/QUOTE]
NOTE: You can do the official updates through the phone as normal without loosing your unlock
Hope you find this info useful