Skydel and newer revision N310's

I’m interested in trying a real-time RF simulation with the Skydel software. I have an Ettus USRP N310 rev. D, which is only compatible with UHD Are there plans to update the UHD version used by Skydel to support newer radios?

Just a heads-up to other N310 users: if mender refuses to patch the rootfs to an older version, don’t proceed to flash the FPGA and downgrade MPM anyway… recovery is less than obvious.

Hello Steve,

For the moment, Skydel uses UHD v, because it is the only version we have tested with success on both X300 and the N310 devices. We know that UHD 3.14 stopped supporting some some sampling rates Skydel uses on the X300, so updating UHD was not possible for us. There is actually no plans to update the UHD version in Skydel, but we will surely consider it if more people are requesting it.

We do have a procedure to flash Rev D N310s such that they can be used with UHD 3.13.1. (This procedure needs to modify the EEPROM of the N310 in order to roll-back it’s revision.) However, you are right, if any error occurs during the flashing process, it is complicated to recover the bricked N310.

Flashing a X300 is much more simpler. Let us know if you could try Skydel on X300 (or X310) instead.

Best regards,

Are there plans to use the version in the near future?

Not for the moment since it’s breaking the backward compatibility with some sampling rate on the X300 device that must be supported by Skydel…


what is the way to go when we want to use the tools that come with the official uhd-host package (e.g. uhd_cal_rx_iq_balance and so on)?

When using your script, only the shared libraries are installed but not these tools. And as the version is outdated, the tools from the official packages do not work in combination with the Skydel set-up which requires an old version flashed to the FPGA:

user@testinstance:~$ uhd_usrp_probe --args addr=
[INFO] [UHD] linux; GNU C++ version 9.2.1 20200304; Boost_107100; UHD_3.15.0.0-2build5
[INFO] [X300] X300 initialization sequence...
Error: RuntimeError: Expected FPGA compatibility number 36, but got 35:
The FPGA image on your device is not compatible with this host code build.
Download the appropriate FPGA images for this version of UHD.
Please run:


Then burn a new image to the on-board flash storage of your
USRP X3xx device using the image loader utility. Use this command:

"/usr/bin/uhd_image_loader" --args="type=x300,addr="

For more information, refer to the UHD manual:


  • Ubuntu 20.04
  • Ettus X310
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My only idea is to download the old source code and compile it on my own, which is quite inconvenient…

It would be nice if you could provide the binaries together with the Drivers.

Hello q-wertz,

Sadly we don’t provide any binaries except the Drivers.

Like you suggested, the solution here would be to compile UHD on your side, which can be quite challenging. You can find the old source code release here on GitHub. All the documentation on how to compile the repository depending on you OS should be there.

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