I know the first thing you gonna say is to google it, there is plenty of tutorials for it, but I tried at least 5 of them (including some in XDA), and every time I didn't succeed.
First of all, here's my HTC Desire status :
BRAVO PVT-1 SHIP S-ON HBOOT-0.93.0001 MICROP-031d TOUCH PANEL-SYNTH0101 RADIO-5.11.05.27 Aug 10 2010,17:52:18
At the beginning, I tried to reinstall the original rom from the links in the XDA : http://forum.xda-developers.com/showthread.php?t=695667
I choosed RUU_Bravo_HTC_Europe_1.15.405.3_Radio_32.30.00.28U _4.05.00.11_release_121865.exe because I'm in France (and it seems it was the most recent version for european).
But when I execute the installer, it works a bit, but then, it fails with this error :
ERROR 140: Bootloader version error (I got it in french : "Erreur de version bootloader")
So after, I tried to get directly the rom.zip by going into the %temp% folder (windows), I put it on the mounted disk of my android, and renamed it to PB99IMG.zip.
I boot with VOL DOWN pressed, and it extract the archive but fails with a :
Main version is older!
So, I must have a newer HBOOT, but I can't find how to downgrade it, and most importantly, to which version ? 0.92 ? 0.90 ? 0.83 ? 0.80 ?
I tried some tutorials, like :
http://forum.xda-developers.com/showthread.php?t=768256 => The link for the downgrader (2.1 or 2.3) doesn't exists anymore, or contains viruses ... great
http://www.mikesouthby.co.uk/2010/08/htc-desire-downgrading-hboot-and-installing-custom-froyo-rom/ => The PB99IMG.zip for downgrading the HTC Desire doesn't work, it result in the same error message "Main version is older!".
In order to sum up, I'm looking for help to make my HTC Desire go back to the ROM I had when I purchased it. For that, I need a link to a tutorial or an app for downgrading to the correct HBoot, and I need to know to which version.
Thank you very much for your help, I really appreciate! I spent 5hours trying to make this work without any luck.