Disclaimer: I'm not an expert, just a student working on a school project.
My zybo z7 board stopped showing up as /dev/ttyUSBx on my linux vm when connected using the UART microUSB port. On my windows host the com port does show up but I cannot open a connection with putty (115200 8n1), no error info or strange characters, just an error sound effect with no explanation. I tried everything on the pc side (driver reinstall, reboot, enable/disable port, different ports, different cables) but I suspect that it is the board not communicating.
I use external power with WALL selected and booted from an sd card with a 500 mb fat32 partition with a boot and image file generated with xilinx petalinux which were not changed from when everything worked fine. There is also a 3gb ext4 partition where the fs is. The only thing that changed before the problem occured is that a few to-be-tested precompiled kernel modules where added to the ext fs in the home folder. Other students with the same set-up do not have this problem. I tried different sd cards and remade the partitions and redid the boot/image/fs generation but no success.
When booting from QSPI the example program works fine so I don't think the board is broken (The serial com doesn't work in QSPI either but I don't know if it's supposed to). Maybe it needs some kind of factory reset? Is there a way to confirm if the microUSB port is working? Help will be appreciated.
btw: upon startup I can see the RX led flickering but never the TX led