Forum Discussion
Having this issue with Quartus 18.1, Windows 10 x64.
Initially USB Blaster is reported as USB-0, adding some FTDI cable forces USB Blaster jump to USB-1, and then its functionality depends on the FTDI device activity - if something is connected to FTDI, then USB Blaster is not found by all the tools (Quartus Programmer, jtagconfig.exe, nios2-terminal.exe, etc).
I tried to play with the order of devices connection after reboot, nothing helped. But then I stumbled upon a sort-of "solution".
jtagconfig.exe has an option to add the programming cable explicitly. That option normally doesn't apply to automatically found usb cables, but this time it worked, maybe because the cable wasn't detected in normal way.
So I did "jtagconfig.exe --add USB-Blaster USB-1" while the FTDI device was connected, and now the cable is found again. Both devices working simultaneously.
The downside is that after FTDI device is removed, you will have two cables - automatically found USB-0 and manually added USB-1, so sometimes you'll have to explicitly select the cable for tools like nios2-terminal. And the "fix" doesn't live across the reboot.