L4T Ubuntu Install guide

What command? If it's a command to install a firmware patch that alters how the hardware works, then it is permanent. Not that there are any firmware patches available, but you should ask the people who told you the command, if you don't understand what it does.

 

"they" didn't tell me, they told everybody:

https://gbatemp.net/threads/l4t-ubuntu-a-fully-featured-linux-on-your-switch.537301/

mid way down the original post:

• NEW: To activate 2 ghz mode run
  Code:
  echo 1 | sudo tee /sys/kernel/tegra_cpufreq/overclock
  echo 2091000 | sudo tee /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq
  then run the command to force max freq if you want to use anything intensive
• 
  
• To always use 2.0ghz mode copy
  Code:
  echo 1 > /sys/kernel/tegra_cpufreq/overclock
  echo 2091000 > /sys/devices/system/cpu/cpufreq/policy0/scaling_max_freq
  
  to /etc/rc.local before the exit 0 line

thats the original post, this one we're in came later done by someone else. they left out A LOT of the info from that main page.
It looks like the "run" command maybe isn't permanent and the "always" one is. But don't know. Then how is the overclock removed and put back to normal, which they don't cover.

And I understand what it does but what you're saying is that these cpu changes occur at the bios level and regardless of what you boot into, once any changes are made, the switch initially boots with those settings for everything and its not determined by what you're booting into telling the switch to "overclock" when you run it?

Cause I know for sure, its not like that for everything. I have a Pi4 with 3 different SD cards and each one will tell the cpu/gpu what speed to run when it boots up. One is stock the other 2 are not. The speed is determined by which card I put in. So technically the Pi always runs stock speed regardless which card I put in, but then a few lines in a file changes that, at boot, depending on what is on that file in the card.

So I want to know if it's definitively that way or not for the switch too.

 

Does this process require a dedicated SD card, or can I use my main?