Yeah, the database thing is a tad strange. I don't know what exactly could be causing it.
I've no windows machine at hand. I've my main machine running Arch with kernel 5.6. Is is possibly an issue upon connection with calibre, with the newer fat driver being coded into the kernel (
https://www.phoronix.com/scan.php?pa...nux-Faster-FAT) is it a dodgy download of the newer firmware (device was just reflashed with latest kernel, and one patch for the annoying chapter and book page details to be swapped)
The observed behavior would be transfer a few books via calibre, normally works quite well. And then, suddenly upon ejecting and the import screen appears and vanishes, the books are not there.
Quit calibre, and reconnect device, mount it, unmount and the books then scan in which is fine but..... eventually calibre will no longer be able to access the database.