Serial device not mounting (Windows 10)


Hi all,

I received my TinyFGPA BX a couple of weeks ago and finally got to hooking it up. I’m seeing a problem where the board isn’t registering as a COM device in Windows 10. I checked the other posts but couldn’t find a solution to my problem.

I’ve followed the setup steps from but when I get to running ‘apio drivers --serial-enable’, the following window pops up:

When I then run “apio system --lsserial” I get “Number of Serial devices found: 0”. Device manager shows the device as “Unknown USB Device (Device Descriptor Request Failed)”.

Has anyone else seen this before or even better does someone maybe have a solution? :slight_smile:

Kind regards


I haven’t seen this happen on Windows 10 before. Are you using a hub? Try using a different hub, port, and/or cable.

Is it an Intel or AMD machine?


I’m connecting directly to the PC’s USB (no hub) and I’ve tried multiple ports and cables. It’s an Intel machine.

I do see something that doesn’t look right when checking libusb:
tinyprog -l --libusb
Traceback (most recent call last):
File “c:\users\admin\appdata\local\programs\python\python36\lib\”, line 193, in run_module_as_main
main”, mod_spec)
File “c:\users\admin\appdata\local\programs\python\python36\lib\”, line 85, in run_code
exec(code, run_globals)
File "C:\Users\Admin\AppData\Local\Programs\Python\Python36\Scripts\tinyprog.exe_main
.py", line 9, in
File "c:\users\admin\appdata\local\programs\python\python36\lib\site-packages\tinyprog_main
.py", line 249, in main
active_boards = get_ports(device) + get_ports(“1209:2100”)
File “c:\users\admin\appdata\local\programs\python\python36\lib\site-packages\”, line 39, in get_ports
for d in usb.core.find(idVendor=vid, idProduct=pid, find_all=True)
File “c:\users\admin\appdata\local\programs\python\python36\lib\site-packages\usb\”, line 1263, in find
raise NoBackendError(‘No backend available’)
usb.core.NoBackendError: No backend available

Any ideas?


I’m reading that the bootloader LED should be flashing but mine just remains on, not sure if this points to a possible problem?


Do you have two lights on or just one?


Both the PWR and BOOT LEDs are on, the BOOT one being slightly dimmer than the PWR one.


Have you tried pressing the reset button on the board to get it back into the bootloader?


Yes, I’ve tried but the LED just always stays on, so visually atleast it doesn’t look like anything happens when I press the button.


Sounds like you got a bum board! No worries, I’ll take care it. :sweat_smile:


Thank you @lukevalenty