UHD Cannot Find a USRP B210: Complete Checklist

[Pavel]

Short answer: Verify USB enumeration, UHD installation and image compatibility before opening GNU Radio. uhd_find_devices should discover the B210 and uhd_usrp_probe should read it; if discovery fails there, application-level device arguments are not the first problem.

Before you start​

• Use UHD discovery and probe utilities before GNU Radio, OpenAirInterface or srsRAN. Save the exact UHD version, FPGA image and device arguments.
• Match the host interface to the requested stream: USB-controller limits matter for B-series radios, while N- and X-series radios require a planned Ethernet path.

Step-by-step method​

1. Step 1: Connect the B210 directly over a verified USB 3 path and confirm the operating system sees the device. Check cable, controller and power if enumeration resets or falls back unexpectedly.
2. Step 2: Run uhd_config_info to record the UHD version and components, then run uhd_find_devices. Close every application and service that could already own the radio.
3. Step 3: Install the image package matched to that UHD release and run uhd_images_downloader if required. Avoid forcing a nonstandard FPGA or firmware image during basic discovery.
4. Step 4: Run uhd_usrp_probe and a modest-rate receive example. Only after these pass should GNU Radio use an empty or serial-specific device argument for the detected B210.

Concrete example​

If the OS sees B210 but uhd_find_devices reports nothing, inspect UHD installation, permissions and images. If discovery succeeds but probe fails during image loading, match UHD and images. If probe passes, troubleshoot the application's device arguments and environment.

How to judge the result​

The device layer is healthy when discovery and probe complete, board information is reported and a sample stream starts repeatedly without USB resets.

What to record​

• Monitor overflow or underflow indicators during a sustained test, not only during application startup.
• Clock and PPS solve different problems: 10 MHz supplies a frequency reference, while PPS supplies a time-alignment event.
• For coherent work, verify phase behavior and timestamp alignment with a known shared signal rather than only checking that two channels display data.

Common mistakes​

• Changing several hardware, software or RF variables at once, which removes the controlled comparison needed to identify the cause.
• Treating one autoscaled screenshot or one unusually good result as proof without recording the settings and repeating the test.
• Copying an FPGA image from another UHD version or USRP family can create a compatibility failure that looks like a missing device.

Final check​

Reboot the host and power-cycle the radio, then repeat discovery, probe and the sustained stream. Keep the exact UHD, firmware and FPGA versions with the working result.