Restoring to stock without booting

[Biffer]

I have a MyTouch 3G Slide that is rooted with S-Off. Recently, the phone has been acting up, with constant reboots. Now, when I power on the phone, it vibrates onces, but the screen does not come on and it does nothing else. I have tried different batteries, and plugging the phone into a charger without the battery (no change indicator). Nothing turns it on. The phone is under warranty and T-Mobile is sending me another unit.

I would like to un-root the device and get S-On before sending it back to T-Mobile. ADB recognizes the device when plugged in via USB.

Is there a way to return the phone to stock through ADB without accessing the bootloader through the phone? I have read the directions on how to return to stock when I can access the bootloader on the phone, but am not knowledgeable enough to restore it through ADB.

I attempted to run the Froyo RUU, but I keep getting a USB connection error. I assume this is because the device is not "on"?

Any help would be appreciated.

Thanks


Sent from my PG86100 using Tapatalk