How can I use the UART ports on Zero 3W?

[iqakb]

Can anyone help me in setting up the UART ports on Zero 3W specifically the GPIO0_D1 and GPIO0_D0 ports? I'm using Ubuntu 22.04 version 5.10.0-1012-rockchip build.

This is my /etc/default/u-boot configuration:

## /etc/default/u-boot - configuration file for u-boot-update(8)
U_BOOT_UPDATE="true"
#U_BOOT_ALTERNATIVES="default recovery"
#U_BOOT_DEFAULT="l0"
#U_BOOT_PROMPT="1"
#U_BOOT_ENTRIES="all"
#U_BOOT_MENU_LABEL="Debian GNU/Linux"
#U_BOOT_PARAMETERS="ro earlycon"
#U_BOOT_ROOT=""
#U_BOOT_TIMEOUT="50"
#U_BOOT_FDT=""
#U_BOOT_FDT_DIR="/lib/firmware/"
U_BOOT_FDT_OVERLAYS="rk3568-disable-fiq-debugger.dtbo rk3568-uart2-m0.dtbo"
U_BOOT_FDT_OVERLAYS_DIR="/lib/firmware/$(uname -r)/device-tree/rockchip/overlay"
#U_BOOT_SYNC_DTBS="false


I have ran sudo u-boot-update then rebooted the board, yet it still didn't work. I was able to change the USB OTG port into a host through modifying the /etc/default/u-boot file, so I'm a bit uncertain on what I did wrong in setting up the UART port.