Dear ZWO,

I am trying to connect and control a brand new EQ6-R Pro over a usb cable yet I can't make AsiAIR to recognise the USB serial port. Everything ended up with the following and setting the baud rate to 115200 didn't help.

I tried the following yet all failed;

Tried 4 different USB type-B cables, 2 came with other ZWO products.
Tested one of the cables on the PC connection and it worked. I also use that cable for my 3d printer, which operates over 115200 baud rate, so the problem is not the cable.
I re-installed the AsiAIR OS 1.4 to a brand new SD card and followed the instructions
I tried to connect the mount over the hand controller and also tried different options and baud rates from the list

As an IT professional, I also tried to debug and able to extract the following information, hope it helps;

dmesg prints the following for the device I plugged my mount;

[    2.541722] usb 1-1.4: new full-speed USB device number 3 using xhci_hcd
[    2.678778] usb 1-1.4: New USB device found, idVendor=067b, idProduct=23d3, bcdDevice= 4.05
[    2.687220] usb 1-1.4: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[    2.694573] usb 1-1.4: Product: USB-Serial Controller
[    2.699725] usb 1-1.4: Manufacturer: Prolific Technology Inc.
[    2.705588] usb 1-1.4: SerialNumber: EFA>xxxxxxx

cmdline.txt enables /dev/serial0 yet the device doesn't have that. ttyAMA0 is the only serial port and the OS is mounting that as /dev/serial1, so I tried to enable /dev/serial1 during the boot but it also didn't help.
stty -F /dev/ttyAMA0 -a reports the initial baud rate of the port as 0
stty -F /dev/ttyAMA0 -cstopb cs8 -parenb 115200 sets the baud rate to 115200 but it also doesn't help with the issue

The raspberry pi docs also states that

Name:   miniuart-bt
Info:   Switch the onboard Bluetooth function on Pi 3B, 3B+, 3A+, 4B and Zero W
        to use the mini-UART (ttyS0) and restore UART0/ttyAMA0 over GPIOs 14 &
        15. Note that this may reduce the maximum usable baudrate.
        N.B. It is also necessary to edit /lib/systemd/system/hciuart.service
        and replace ttyAMA0 with ttyS0, unless using Raspbian or another
        distribution with udev rules that create /dev/serial0 and /dev/serial1,
        in which case use /dev/serial1 instead because it will always be
        correct. Furthermore, you must also set core_freq and core_freq_min to
        the same value in config.txt or the miniuart will not work.
Load:   dtoverlay=miniuart-bt
Params: <None>

I believe I don't need to enable this at all but I wonder if that's the case.

TL; DR; I am stuck at this point. I have another raspberry pi 4 model B as a spare but it seems the licenses are also hardware locked, so I don't think I can test the hardware by simply switching the board. Please let me know how to proceed.

Best,
Tim