How do I edit /proc/cmdline ??

I want to edit /proc/cmdline
Edit with the following command causes an ‘input / output error.’
$ sudo nano /proc/cmdline

origin : “console=ttyS0,115200n8 console=tty0 OS=l4t fbcon=map:0 net.ifnames=0”;

to edit : “console=tty0 OS=l4t fbcon=map:0 net.ifnames=0”;

You cannot edit /proc/cmdline. This is not a true file, but a pseudofile.
It shows the arguments passed to the kernel.

If you want to try new kernel arguments, you would edit /boot/extlinux/extlinux.conf and add an entry for an alternate config.

Use a serial console to choose your alternate config with u-boot.
Once you are confident it works fine, then you would set this config as default, so that it will boot this one and you will no longer have to use serial console.