I'm reaching out as a last resort. I think this nuvi is bricked beyond repair, so at this point, I'm willing to try anything

Standard questions:
1) Nuvi 265WT, 7.60 firmware, 0827 hw id
2) On Friday, I updated the firmware, maps, and additional files (voices, etc.) in preparation for a trip. Upon reboot, it showed "Loading maps..." until the battery died (4 hours or so). I tried many ways of reseting it, hard reset (lower right corner of screen), reset button under bottom label, holding the power button for 30+ second. No matter what, it would not enter mass storage mode. It would just stop at loading maps. Screen calibration mode worked for about five button pushes, and then it stopped doing anything. So after reviewing many forum posts, I used GarminCure3 to flash back to the original 7.60 firmware in pre-boot mode. The updater ran, but then crashed in the end with a IOU_UTILITIES.CPP-203-2.8 error. (I could hear the two tone down usb dismount when it hit 100%). Reboot resulted in loading maps hang again. So I tried a cure firmware of 7.6. Same thing. Then I tried a 6.6 (I think) firmware for the 0827 hardware. It ran through to 100%, and then started over, and took 30 minutes to install the firmware. Then it just hung at the end. When I rebooted, it gave me the missing system software error. I spent 2 hours on the phone with Garmin trying to flash it back into existence with the 7.60 firmware. Nada. The tech said that after it hits 100%, it should disconnect and then reconnect to the USB. It doesn't come back up, though. The device shows "Loader" (not "Loading Loader"
3) "System Software Missing" is the message.
4) It will only be detected in Windows when I'm in pre-boot mode.
5) See above.
6) Yes, per the Garmin tech.
7) G7ToWin returns details above. When it isn't throwing "USB Error: WaitComplete: Error Waiting for ERROR_IO_PENDING" or "USB Error: open_Garmin_USB: Failed getting USB Handle"
8) "How to unbrick nuvi" run several times.
9) Yes, I can reach pre-boot mode (I'm assuming it is pre-boot mode. It does what I expect in that mode, that is.)
10) No NV backup.

Any thoughts?