Just want to share my experience as to how I rooted my HTC Desire (A8181 GSM).
Before I continue further, some key factors and reasons for rooting the phone:
- A better or functional "recovery" menu compared to the stock
- With the recovery, I could create/restore a backup image via Nandroid.
- Using a different OS image available around the net (i.e. CyanogenMod, Oxygen, etc.), but you can stick with your stock rom like I did (HTC sense lol!)
- replacing my stock Baseband version (for signal and battery performance)
- Root permissions of course
- USB cable
- phone must be at least 30% charged (but don't push your luck on this, just charge it to the most you can)
- "unrevoked" application (you can search it via Google or get it here)
- RA-desire-v2.0.0 recovery image (highly suggested; Google it)
- HBoot Drivers (only for Windows users; can be downloaded on the unrevoked website)
- extreme levels of caution and patience
Once you have all these stuff prepared, you have to perform the following changes in your phone...
- enable USB debugging inside "Settings" -> "Applications" -> "Development"
- enable Unknown sources inside "Settings" -> "Applications"
- set default connection type to "charge only" and uncheck "ask me" in "Settings" -> "Connect to PC"
- backup your sms messages and other stuff (your data in the SD card is safe)
- no need to remove your SIM card and SD card
- Run the unrevoked3 application (for Linux users, it should be in "sudo")
- [For Windows only] install the HBOOT drivers, so that your PC can correctly detect your device
- On the menu, select "Custom recovery" (similar to this wording) and select the RA-desire-v2.0.0 image from the directory you saved it. There will be a "custom" indicated in the bottom center of the unrevoked application if you did this part correctly.
- with your Desire turned on, connect the phone with your data cable and onto the PC
- upon connecting the phone, the unrevoked application should detect it and prompt a message in which it will be a go or no-go confirmation. Hit the ok button or yes (or whatever)
- the unrevoked application will now commence the rooting, just watch your phone and application, and NOT touching your phone or anything
- wait for it to finish
- yes... wait a bit more... it will restart on its own and do some stuff by itself even more...
- it will probably be already at a portion testing or doing a "root"... wait for it...
- it should be then loading and replacing your recovery menu
- wait for the unrevoked application to be "Done" (literally)... just wait until there's a "Done" shown on your PC screen.
To resume to your normal usage, just let it "reboot" and you're good to go again.