If you have 2.1 ROM installed and...

Well they should have done a nandroid backup before installing 2.1 so they should be able to just do advanced nandroid restore in sprecovery

 

I thought it was as simple as the Bugless Beast rom would replace the 2.1 rom when you an update.zip or the nandroid method.

 

Just found out I was mistaken. Beast installs over 2.01, not over 2.1.

Sorry, so this is what it feels like to make a mistake!!

 

dont you just wipe system and cache before doing the nandroid restore?

 

I had 2.1 running before I went to BB. I deleted the 2.1 folder out of nandroid, then copied in the BB 0.7.2 (I was using at the time), and then I did a system wipe, cache wipe, and simple restore to BB 0.7.2. Worked great.

Everytime I do an upgrade, as a rule of thumb, I always do a clean wipe. I've learned from my BlackBerry Storm days, that clean wipes always make for a better experience, even if you have to spend a bit more time restoring back things. The way I feel is if someone didn't want the hassle of restoring things, don't bother hacking your phone because that is always a possibility you loose what you have.

 

you should be fine if you wipe data and use the nandroid restore then update.zip method would need you to roll back 2.1 to 2.0.1 though