Any idea how to mount the device?

[sanchosk]

Your tool looks interesting, however I have different problem.
I have the version 20201111000001 of the MP3 player, but when I plug it into Ubuntu, the dmesg recognizes it but reports data read error and then the mp3 player reboots in endless loop.
I tried multiple SD cards.
When I plug the card into card reader and copy music to it, the player recognizes it and plays no problem.
Any ideas what might be the problem, please?

[ilyakurdyukov]

Yes, I have the same problem with SL6801 devices: they do not mount in Linux. I think the driver from Linux sends a command unknown to the firmware, the firmware rejects it and closes the connection.

There are many such cases when cheap Chinese devices work correctly only under Windows. For example, many Bluetooth USB adapters.