Quote Originally Posted by Aurih View Post
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The PC cannot see the device, but I hear it connect when I start the Garmin while holding the lower right corner. It will say " System " on the screen above the logo for three steps down and then the movement of the word " System" stops for a moment. It will then say "Loading" and I hear it disconnect from the PC USB connection. I have to unplug both the USB and the battery to get it out of "Loading' mode.

I was only able to get G7ToWin to be able to read it while the word "System" was on the screen.

I have yet to try the Garmin Cure program due to being uncertain which firmware to obtain.

If by Preboot mode you mean when it says "System" and or "Loading" I have found that
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The device is in preboot when "System" shows briefly on the screen. G7ToWin only detects devices in preboot so that's already confirmed. To re-enable Mass Storage Mode it MAY be necessary to load Cure firmware and re-format however because of your detailed backstory the problem is likely not due to a faulty file/s in the on-board memory, rather region 14 where the main system software is stored might be corrupt or incomplete. That can be due to the device running out of power while coincidentally attempting to boot up. In that case of corrupt firmware, the device if otherwise healthy, defaults automatically to preboot mode so if you didn't need to hold the screen while powering on to reach preboot you'll simply need to re-flash the original firmware but as an RGN file using Updater.exe. You can convert a GCD file to an RGN using RGN_Tool or do it easily with kunix's Cure3 software. You can confirm the device is in preboot by observing Device Manager where it will appear under "GARMIN Devices". It will likely only retain preboot (showing System) for a few seconds so you'll need to move quickly to flash it.

Note: If it is indeed faulty firmware, it may be able to be flashed by text command via microSD if all else fails however usually that isn't possible, because for that process we use Ldr.bin (aka boot.bin, the ramloader) which is initiated by region 14 (fw_all.bin) and that's the same region you will be trying to flash. There are other ways to do that too however, but try flashing as an RGN file first.