Kobo Wireless won't show any books

I've got an old Kobo Wireless that I lent to a friend at work, and today it seems to have crashed.

Seemingly out of nowhere, it stopped displaying all of her books. Most of these were sideloaded onto the internal memory, but it also won't display the 100 free books that came hardcoded into the device. It won't even show the option to hid the free ebooks!

I brought it home this evening to find that the Kobo memory was totally empty - not even system files (metadata, etc). I tried loading books on, and when the device starts up it goes straight to the library, which is empty. After plugging in the device again and trying to load the epubs in Sigil, they open properly, which leads me to believe it's not a failed internal memory.

I've tried doing a factory reset as well as the pin-in-hole method, and neither of them have helped. It won't synch to Calibre (it throws an error) or to Kobo Desktop (doesn't even notice anything had been plugged in - I assume the Wireless is no longer supported). I am using firmware 1.9.11.

So, has the device just insisting on retirement, or is there potentially a fix for this? Any help would be appreciated. Thanks in advance.