How to change the console baudrate of cm3s?

Hello.

I mounted the cm3s to the io board.

Flashed the most recent Debian image (radxa-cm3-sodimm-io_debian_bullseye_xfce_b24.img).

Connect the ch340 module to the console pin and set the baudrate to 1500000 to check message input/output.

I want to change the console’s baudrate.

When I flashed the Ubuntu image for cm3s,
Enter ‘sudo nano /etc/kernel/cmdline && sudo u-boot-update’ to confirm that the baudrate of the tty device is changed and saved.

After downloading the Debian image, even if you follow the same method as above, the contents of the file change, but the actual baudrate doesn’t seem to change.

Is there any other way?

++
I flashed the ubuntu image again and it still doesn’t work.

When I type the stty command, any speed other than 115200 returns an error like ‘stty: ‘standard input’: unable to perform all requested operations’.

How can I solve this problem?