How to downgrade ROM so I can return Phone

[sandshrimp]

I just got a replacement XDA from T-Mobile and I have to return my curretn XDA that has 4.00.16 on it. What's the easiest way to downgrade the ROM to the original T-Mobile ROM?

Can I use the new XDA somwhow to do this?

Thanks

[cruisin-thru]

You could go to bootloader mode, copy ce to sd card with the new phone then bootloader the other phone with that sd card in and then do sd to ce.

[valheru]

Or just take the backup you made prior to updating, because you would not have been crazy enough to do anything prior to backing up, and use XDA Tools to burn the old ROM back to your device.