Verdin imx8mm Dahlia UART3

I want to use UART3 on the X20 of my Dahlia board. I assembled R333 & R334 and disassembled R327&R328.
When i want to access the /dev/verdin-uart3 i got a ‘permission denied’ exception.

/dev/verdin-uart1 & /dev/verdin-uart2 are working.

It’s happened because UART3 is a defauilt debug (console) for the main OS (Cortex-A).

From the Verdin iMX8mm datasheet:
UART_3 is in the “Always Compatible” section and is intended to be used for the main OS terminal
(A53 cores) as a debug port. It could be used for general purposes, but we recommend making
this interface available for debugging purposes. UART_4 is in the “Reserved” class. This interface is
intended to be used for the real-time operating system (M4 core). The interface may be used as
general-purpose UART.