BladeRF Micro A9 not working unless connected via USB hub

[Marshall925]

Environment
• Device: bladeRF Micro A9
• OS: Windows 11 Pro 23H2 (x64)
• PC: Lenovo ThinkCentre M90q Gen 6 (Type 13AD)
• USB Controller: Intel USB 3.2 Gen 2 xHCI
• bladeRF-cli version: latest (from official installer)

Problem
When I connect my bladeRF Micro A9 directly to the rear USB 3.2 ports,
the device appears correctly in Device Manager and bladeRF-cli -p shows it,
but any operation (including FPGA load or simple stream) fails with errors like:
C:\Program Files\bladeRF\x64>bladeRF-cli.exe -i
[ERROR @ host/libraries/libbladeRF/src/backend/usb/nios_access.c:69] Failed to send NIOS II request: An unexpected error occurred
Read Error -5

Question
Could this be a known Intel xHCI compatibility issue?
Is there a possible firmware or driver-side workaround for Windows hosts?
Thanks a lot for maintaining bladeRF — any help or advice would be appreciated!

[felixandrea]

That honestly sounds more like a USB signaling/power negotiation issue than a bladeRF software problem, especially since it works through a hub.

I’ve seen similar behavior with some Intel xHCI controllers where direct USB 3.x connections behave badly with SDR devices, but putting a powered USB hub in between stabilizes timing enough for transfers/FPGA access to work correctly.
heardle
A few things I’d try:

disable USB selective suspend in Windows power settings
disable USB power saving for the xHCI controller in Device Manager
force the port to USB 2.0 mode if possible
try a different cable (bladeRF can be surprisingly sensitive to marginal cables)

The “Failed to send NIOS II request” / Read Error -5 usually points to communication instability rather than FPGA corruption from what I’ve experienced.

Honestly, if the hub works reliably, many SDR users just keep using one permanently.