Directions to edit cmdline don't work

[nightduck]

Following these instructions:

reference-system/README.md

Lines 133 to 143 in a25f704

	dd if=/boot/firmware/boot.scr of=boot.script bs=72 skip=1
	# edit boot.script and modify bootargs to
	ubuntu@ubuntu:~$ cat boot.script | grep "setenv bootargs" | head -1
	setenv bootargs " ${bootargs} rcu_nocbs=2,3 nohz_full=2,3 isolcpus=2,3 irqaffinity=0,1 audit=0 watchdog=0 skew_tick=1 quiet splash"
	# generate boot.scr
	mkimage -A arm64 -O linux -T script -C none -d boot.script boot.scr
	# replace boot.scr
	sudo cp boot.scr /boot/firmware/boot.scr

On a Pi 4 running Ubuntu 20.04 will not change the cmdline. Instead, you must edit /boot/firmware/cmdline.txt to say

zswap.enabled=1 zswap.zpool=z3fold zswap.compressor=zstd dwc_otg.lpm_enable=0 console=tty1 root=LABEL=writable rootfstype=ext4 rootwait fixrtc rcu_nocbs=2,3 nohz_full=2,3 isolcpus=2,3 irqaffinity=0,1 audit=0 watchdog=0 skew_tick=1 quiet splash

Reboot and the changes will be in effect. This fix is tested and confirmed working for me.

It's unclear if this is a distro issue between Ubuntu and Raspian.

5 weeks from now, I'll have free time to investigate myself. For now, I'm documenting the issue.

[razr]

Thanks @nightduck for reporting it. I'll look into it next week.