Issue with bladeRF and Raspberry Pi 4 – power supply failure when connecting grounds

[juanmont329]

Hello everyone,

I would like to ask for advice regarding an issue I recently had with my bladeRF setup.

Setup description:

SDR: bladeRF (please confirm: x40 / micro xA9).

Host: Raspberry Pi 4.

External device: function generator providing the synchronization signal.

The Raspberry Pi was powered by a USB wall charger.

The bladeRF was connected to the Raspberry Pi via USB.

The function generator was connected to a small board that drives a transistor to provide the sync signal for the SDR.

What happened:
When I connected the ground of the function generator with the ground of the SDR/Raspberry Pi system, the Raspberry Pi’s charger failed/exploded.

Current status of the bladeRF:

The board is still detected over USB.

I am able to load the firmware.

However, the FPGA does not respond and cannot be loaded anymore.

My questions:

After this kind of event, does it sound like the FPGA portion of the board may have been permanently damaged?

Are there any recommended steps to check if the FPGA is still functional or if the board can be revived?

Could this have been caused by a ground loop or potential difference between the generator ground and the Raspberry Pi/bladeRF ground?

Would you recommend using isolation (transformer, optocoupler, or USB isolator) when injecting external sync signals to avoid this issue in the future?

If the FPGA is not responding, is there any recovery procedure (JTAG, test pins, etc.) that I should try before assuming permanent damage?

Thanks a lot for your help and guidance