It was worth trying to read the dumped BINs but that result is not very surprising. The file system regions are now certainly confirmed corrupted/unreadable. That was previously indicated by failure to dump copies of GCD and XML files with 'volume not mounted' error.

Maybe it's appropriate to try deleting the file system by erasing the regions using "ergn,48" and/or "ergn,83". If it succeeds, that would however result in a region state similar to an unformatted/unallocated partition in Windows or reported as a RAW volume in Disk Management if it can be detected, so we'd then need to have Mass Storage Mode available to re-format the file system with RMPrepUSB or it may even be required to recover it by doing a LLF with a different tool. We could also erase the main firmware (system software) in region 14 to force it to default to preboot showing 'System Software Missing'. You may want to think about whether to do either or both, and if so which to do first. I suspect that erasing the file system regions won't make things any worse, maybe... but erasing the firmware in 14 is very risky as it's quite impossible to know how much the wrong firmware data there is contributing to the present partial operation of the device, or, if it's in fact hindering further functionality. However if it loses preboot or media card function again it might be quite problematic. I'm certain losing both would be fatal. At least with the cure fw presently loaded to region 14 it might be possible to re-gain Mass Storage if the file system is empty of any data preventing the device booting and/or trying to load software during the boot attempt.

Another thought is to attempt to overwrite the file system using 'fftl' text command. I'm unsure what exactly is additionally executed with that command other than just writing a BIN file's data to the file system. It seems it must do something more that just write data from a BIN to a region because that's what 'xrgn' does. So fftl command may also properly format the file system before writing to it i think. Maybe it doesn't work like that, i just am not sure. If you want to try it, it's best to compile a BIN file named filesystem.bin, comprised of just .System and Garmin folders because many devices won't boot completely empty and we want it to boot, eventually. This zipped bin has been made with PowerISO or you can make your own: [Only registered and activated users can see links. ]. Usage: Extract the ZIP file and place filesystem.bin in card root alongside (not in) the Garmin folder. Remove last_id.bin if present in 2512 folder and replace Update.txt content with "fftl,0,1:/filesystem.bin".

If you try any of the above suggestions i can't say what the results might be so you have to take all responsibility for any outcome. I doubt you have much to lose at this stage anyway.