Yes, DS61 and DT71 both have HWID 2588 and use the same firmware. However Garmin's servers still only offer V6.30 so please state if you intentionally advanced the version number when using the patcher, or is it a new device with factory loaded V6.40? I suspect it's the latter in which case if the device has defaulted to preboot mode the main system software in region 14 (0x0E) may be corrupt or missing. As therefore it certainly is under warranty you should just return it to Garmin for exchange explaining it bricked while updating. They won't return yours, you'll get a new or refurbished 71 back and they'll send yours off for factory refurbishment without question.