2.2 back to 2.1 (Rooted Phone)

Hello All:

  I have a rooted Eris and I need to go from Kaosfroyo 2.2 back to the verizon 2.1 version...does anyone know how to do this and can explain the steps needed?

  I tried last night putting the PB00IMG.zip back into the ROOT of the SD and then using the RUU, but when it goes into the BOOTLOADER, it shuts off the connection to the USB, and when it tries to boot up the phone, the computer has to re-install the USB driver which then causes the RUU to timeout due to how long it takes to get the USB back up and running...

  Is there an easier process, am I even trying to do it right, and if not...what do I need to do to get this back to 2.1?

Thanks a million!!!!
Scott

Yea, i tried that and it was not working....Anything else you can offer or tell me step by step so I can see what I might be doing wrong?

**UpdaTE:  Does the 2.1 image i want to re-install have to be named PB00IMG.zip or Update.zip...I have seen both but not sure...

  When getting to the BOOTLOADER  it tells me NO Image FOUND, meanwhile the PB00IMG.zip is in the Root odf the SD card...

Should I re-format the SD card....WHICH is something else I read on Android forums as well...

**UPADTE: After putting the PB00IMG.zip into the root and trying to boot using the VOL DOWN and POWER, I got this message:

Phn just displayed a message MAIN VERSION IS OLDER: UPDATE FAIL!

Do you want to reboot your device?

Did you try this?
http://www.droid-eris.com/roms/retro1rom-1-5-cupcake/

Are you guys sure the 1.5 rom will unroot me if I need it

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