M4 stops responding after linux boots on A7

After booting the M4 from u-boot it stops responding on UART-B after linux boots.
The 4.9 kernel doesn’t exhibit this behavior, only the 5.4 kernel. We’ve checked using both TCM and OCram.

We’ve tried the hello-world demo and a simple counting demo. They both stop outputting to UARTB after linux boots.

Thank you

Greetings, @CMR!

We are aware of issues with some M4 examples and our BSP team is currently working on a fix.
However, the hello-world demo should work. Did you disable UART_B on the device tree?