FYI: I successfully connected my Epos 2 (running latest official firmare v14.1) via fastboot on (Arch)Linux! It's easy, no special drivers required:
1.) Connect device via usb and then power it off.
2.) Run the fastboot command now!! It will wait until the device is available...
3.) Turn on and keep power button pressed until you see progress from fastboot.
That's it.
The problem is: the usb fastboot device will be visible only for a the short time (mabe 5 seconds):
Code:
[33875.750154] usb 3-1: USB disconnect, device number 59
[33914.076001] usb 3-1: new high-speed USB device number 60 using xhci_hcd
[33914.216611] usb 3-1: New USB device found, idVendor=18d1, idProduct=0d02, bcdDevice= 3.11
[33914.216623] usb 3-1: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[33914.216627] usb 3-1: Product: i.mx6sl NTX Smart Device
[33914.216630] usb 3-1: Manufacturer: Freescale
[33914.216633] usb 3-1: SerialNumber: xxxxxxxxxxxxxxx
If no fastboot connects during that time, the usb device will vanish and it boot normally as mass storage device:
Code:
[42958.272368] usb 3-1: new high-speed USB device number 82 using xhci_hcd
[42958.421663] usb 3-1: New USB device found, idVendor=1f85, idProduct=6052, bcdDevice=99.99
[42958.421682] usb 3-1: New USB device strings: Mfr=2, Product=3, SerialNumber=4
[42958.421686] usb 3-1: Product: tolino
[42958.421689] usb 3-1: Manufacturer: Rakuten Kobo Inc.
[42958.421692] usb 3-1: SerialNumber: xxxxxxxxxxxxxxxxxx
[42958.429295] usb-storage 3-1:1.0: USB Mass Storage device detected
I booted into an ADB-enabled image this way and then I permanently enabled ADB via Android Developer Settings. No need to flash and brick anything.
Now I'm very happy with KOReader on the device :-)
Setting up ADB might be a bit more complicated on Linux though. Had to create proper udev rules specifically for the device following the guide here:
https://wiki.archlinux.org/title/Android_Debug_Bridge