Beaglebone AI Wifi not available with RT kernel

I am installing the real time kernel on the Beaglebone AI, but whenever I do the wlan0 device is lost.

I start with a Debian 10 system running kernel 4.19.94-ti-r68. Here the wlan0 device is fully functional and visible from ifconfig, ip etc, When I update to 4.19.94-ti-rt-r68 and reboot to switch to the new kernel the wlan0 device is not visible anywhere. I have tried the update using the apt install method and using the script with the same result with both.

Am I missing something here? Do I need to manually install firmware after update?

Hi @jhorne this is sadly a known issue with the brcmfmac patchset…

Cypress just re-freshed their brcmfmac patch-set for v5.10.x a few days ago, please test:

sudo apt update
sudo apt install
sudo reboot


Hi @RobertCNelson thanks for getting back to me so quickly.

I have tried the above, but have come across some issues. I am starting with a clean debian 10 installation (kernel version 4.14). All attempts at installing 5.10-ti-rt-am57xx have resulted in hang on boot after the reboot. Installation of the most recent non-real-time 4.19 kernel is successful. After installation of non-real-time versions of 5.4 or 5.10 kernel I lose WiFi and the ssh over USB facility. I did try the previous 5.4 release but encountered the same issue.

Are any of these known issues? Is it worth me working back through the 5.x releases until I retain WiFi and ssh over USB?


Hello, is this still a thing? Is there now a way to have RT kernel and a fully working BB AI?

Correct, broken cypress drivers…