Factory release for Aura H2O Edition 2 Version 2 and Aura Edition 2 Version 2 only. Download links are currently not available.
Do I have a Version 2 device?
If you have 4.6.10197, you have a Version 2 device. The 7th digit of the serial number of Version 2 devices is also always a 2. The USB ID is 0x401.
What is different about Version 2 devices?
They have a different CPU: i.MX6 SLL. The product ID is 378 and 379. The USB ID is 0x401.
Are Version 2 devices compatible with mark 6 firmware
Maybe.
Calibre does not detect my device
Update it to v3.20 or later.
Thanks to davidfor's post here.