That's a pointless hope because WebUpdater CANNOT flash firmware directly to the device regions. It merely places a gupdate.gcd file into the .System folder. The device will check and if appropriate will process the GCD on the next COMPLETE BOOT CYCLE. So if there's no subsequent boot, there can be no flashed regions via WebUpdater, or GarminExpress. Only (i) Updater.exe [using PREBOOT] or (ii) Ldr.bin [on media card, read by the device DURING BOOT] can flash fw directly to the device's regions to replace existing firmware.

An empty Garmin folder in the root of the device is what i meant in Post #23, i didn't mention the card in that suggestion. Many modern Garmin devices cannot boot completely empty and require at least a 'Garmin' folder on-board.

About the use of media card for recovery flashing: The simple fact is that the GarminDevice.xml you uploaded shows that this device now has HWID of 2826 so if you are absolutely certain that it doesn't read a folder named "2826" in sd:/Garmin/Updater, then unfortunately it's not recoverable by SD card method. That will be because it's not booting far enough to even see the card before entering Mass Storage Mode, even though it's not connected to PC.

Preboot on the other hand is attainable very soon after powering on and before the actual boot sequence starts (hence the name "preboot"). That's of course much earlier than when the device looks for a media card during the actual boot cycle. However in a malfunctioning device like yours, that point where preboot is attainable is only very fleetingly available.

Therefore, without opportunity for a card recovery, your only hope to recover this device lies in using preboot to force-flash with an RGN file and return it to DS50. If you are very persistent, you might be able to catch preboot for long enough to initiate a flash from Updater.exe. When Updater.exe and the device start a data communication the device will hold preboot until the flash finishes unless it's sooner interrupted by a disconnection.

That very brief moment after power-on is when the device has the capability to enter preboot, and that's before the computer image appears on its screen. Boot-looping constantly re-starting devices are similar to your DS in being very difficult to attain preboot, it once took me many dozens of attempts to catch preboot in a boot-looping nuvi. Once i did catch it though, a successful flash was the result.... but it took a lot of patience. If you don't feel you can be persistent and patient, prepared to make many repeated attempts, you may as well now strip the device for usable parts like screen and battery then dump the board. If you want to press on then preferably use a desktop PC and follow these instructions EXACTLY:
  • Ensure the device is fully OFF by holding the power button down for an extended period;
  • Extract this RAR file [Only registered and activated users can see links. ] then open the folder "Updater" to find OUT.RGN and Updater.exe;
  • Drag the RGN file onto Updater.exe to open its GUI;
  • Select the radio button next to "USB Device" and leave the GUI open and visible on your PC's desktop with the mouse cursor hovered over the GUI's "OK" button;
  • Plug a 'known-good' USB cable directly into a REAR USB2 port of the PC (don't use a front port, a hub or a USB3 port);
  • Position your left thumb in the correct place on the device screen, press and hold firmly while plugging the cable into the device with your right hand then very quickly either move it to the mouse ready to click the ok button or be ready to hit the Enter key of the PC keyboard while closely watching the window next to 'USB Device' on Updater's GUI and keeping firm steady pressure on the device screen;
  • The very moment you see the device's detail appear in the GUI window, click ok or hit enter key to start the flash. Don't release the screen if the flash starts, hold it steadily until 'Success' message is given by Updater.
  • If the device details don't appear in, or do appear but immediately disappear from, the GUI's window it means you've missed the moment so just repeat the entire process from step 1.

Good luck.