Hi guys, new here, and somewhat new to Garmins.

I recently acquired a Nuvi 780 @ a freight recovery auction. It worked, but it looks like it belonged to a rental company, and possibly had custom firmware as many features were missing. Software version did say 2.90.

To recover the missing features, I attempted to use webupdater, and it said there were no updates available. So I tried copying a 760 GUPDATE.GCD to the garmin folder (onboard storage), but it ignored it, and booted as usual. I downloaded the nuvi760_490 firmware, extracted the rgn, and used updater.exe to flash it in USB pre-boot mode. It uploaded, said the update was successful. The device went to "LOADER LOADING..." and hung. Forced a reboot, and now it says "System Software Missing". I tried the fixes mentioned around the web with numerous firmware versions including CURE, but I'm stuck.

Cant hard reset, cant get to screen calibration mode, Cant get into mass storage mode of any kind. I CAN get into pre-boot usb mode, flash with updater.exe, but it never gets past "Loader Loading" and is stuck in this loop.

Another thing I've noticed is updater.exe will only upload the rgn if its named "075401000XXX.rgn", if I remove the XXX's and replace with the version, it says no updates are available and quits.

Is it toast? What is boot.bin and fw.bin? Do these need to be renamed and uploaded also?

Thanks for any help!