With Zephyr, I am using BLE Stack sample (rpc-host) on net core and peripheral_uart on app core. I changed the uart pins on from the standard dvk configuration on devicetree files to new pins in order to test using an external uart converter to RS232. I removed the same pins from appcore's devicetree. The console is not sending anything to these new pins. 
These are the pins configuration on cpunet-pinctrl.dsti --->
&pinctrl {
uart0_default: uart0_default {
group1 {
psels = <NRF_PSEL(UART_TX, 1, 8)>;
};
group2 {
psels = <NRF_PSEL(UART_RX, 1, 9)>;
bias-pull-up;
};
};
uart0_sleep: uart0_sleep {
group1 {
psels = <NRF_PSEL(UART_TX, 1, 8)>,
<NRF_PSEL(UART_RX, 1, 9)>;
low-power-enable;
};
};
On cpunet.dts --->
chosen {
zephyr,console = &uart0;
zephyr,shell-uart = &uart0;
zephyr,uart-mcumgr = &uart0;
zephyr,bt-mon-uart = &uart0;
zephyr,bt-c2h-uart = &uart0;
zephyr,sram = &sram1;
zephyr,flash = &flash1;
zephyr,code-partition = &slot0_partition;
};
&uart0 {
status = "okay";
current-speed = <115200>;
pinctrl-0 = <&uart0_default>;
pinctrl-1 = <&uart0_sleep>;
pinctrl-names = "default", "sleep";
};
On main.c there is only this:
#include <zephyr/sys/printk.h>
void main(void)
{
printk("Starting nRF RPC bluetooth host\n");
printf("TEST 123 \n");
}
Everything works well, but I can't see any console messages coming from netcore.
