HTC Tattoo : Can I Roll Back To An Older ROM?

I stupidly installed the Orange ROM update on my Tattoo and am now having the issue with it only ringing once. Is there anyway I can roll back to an older ROM? I've downloaded V 1.65.405.1 but the phone won't let me install it. I remember on an old SPV phone when I was trying to remove the Orange branding I had to unplug it when it was trying to do the ROM update which corrupted the phone and allowed me to install the unbranded ROM. I'm wondering if doing that would work but I don't wanna risk it.