You now have a backup of your stock android ROM, the next step is to install a custom ROM to the phone.
To do this go to the xda-developers.com website and find the ROM you want to flash to your phone. (I am currently running MoDaCo 3.1).
Download the ROM you want to your PC. The ROM will be a zip archive, do not extract it but do rename it to update.zip.
Plug in your phone and pull the update.zip file to the root of your SD card (do not put it in any other directory).
Unplug the phone and turn it off.
Boot the phone while holding down the Home and Power buttons to get back to the recovery screen
First select "Wipe" from the menu, this resets the phone to factory defaults (don't worry, you can use the nandroid backup you preformed earlier to get back to the exact state you were in before you started).
When the wipe is complete select "Apply Update.zip" and let it run.
When it has completed reboot the phone.
First boot on a new ROM usually takes a while longer than usual, don't panic, let it run.

You now have a rooted Hero with your choice of custom ROM. By preforming nandroid backups/restores you can switch between ROM versions without loosing data.

PLEASE NOTE: I take no responsibility for any damage caused to your device as a result of following the steps above. When following the guide on theunlockr.com read the text. The steps have been updated but the video does not reflect this change.

I had read a lot about people rooting their Android phones and installing custom ROMs. I had also read that there was a leaked Android 2.1 ROM available for the Hero so needless to say, it wasn't long before I started messing about with the phone and trying to work out the steps to getting a custom ROM on to it.

The first stop for anyone interested in gaining root access to their Android phone should be xda-developers.com. The forum specific to Android Development for the HTC Hero can be found here.

My Hero was running the official HTC 2.73.405.5 ROM and had the 63.18.55.06EU_6.35.06.18 radio version installed. The phone was not SIM locked to the meteor network.

After quite a bit of reading on both xda-developers.com and some other links that I found from searching around with Google I decided that I knew the steps to getting root access to my phone.

The first step is to get Amon's RA-hero-v1.5.2 custom recovery image onto the phone. I followed a guide on theunlockr.com which used FlashRec 1.1.3 to flash the recovery image to the phone. There is a notice on the FlashRec webpage that reads:

"Please note that current firmwares are patched. If you still have a phone with a cupcake (1.5) firmware, FlashRec may still work, but there are some patched cupcake firmwares too. If you get “Could not run command”, then your firmware is patched."

However it worked no problem with my Hero from meteor.

I now had the custom recovery image running on my phone. Restarting the phone while holding down the Power and Home buttons popped up the "Android System Recovery" menu.

PLEASE NOTE: I take no responsibility for any damage caused to your device as a result of following the steps above. When following the guide on theunlockr.com read the text. The steps have been updated but the video does not reflect this change.