How do I boot into Kubuntu 20.04 after installation?

[catterkun]

I use a Samsung Chromebook and have installed 20.04 to a USB stick. (32GB, in case that helps any) I'm not sure how to access it when it's done and it reboots. I've tried using CTRL+L in developed mode and booting into the USB, but it brings me back to the test/non-installed version. Help?

[Snowhog]

20.04, or 22.04? You posted in 22.04, but your Topic Title and your query says 20.04. Which is it?

[claydoh]

So, you installed using two USB sticks, one with the ISO installer, and the other used as the destination for the OS?
Did you point the boot loader option to the destination USB when running the installer?

I assume you have done all the required firmware and bootloader modifications on the Chromebook?
Which specific model?

If the USB stick is booting to the live installer session, the either you did not install the OS successfully, or it installed to the Chromebook's internal storage.
The USB you are booting is the installer disk, not the OS disk.

[catterkun]

It's on a Micro SD card that's also in the Chromebook, do I have to use 2 USB's?

[claydoh]

Maybe.
One for the installer, one as the OS drive.
Only one to run the OS from when you are done.
The device might not like booting from the sdcard. I have seen that, or it simply does not support this at all.

Or you didn't point the bootloader to the sdcard during the install.
You need to make sure this option is set, using the section at the bottom of the image here. It needs to point to the same main device that the root partition is on., mmcblk1 (or 0) most likely for the sdcard.,

or maybe having the USB installer plugged in took precedence over the sdcard? Chromebooks do not have very complex firmware, and don't have fancy system options.

I have had Chromebooks that didn't boot to the slot, but even on those that do, sdcards are bloody terrible for running on OS from --based on trying to do so.

A low-profile Samsung FIT is a good, reliable choice for a USB stick at a decent price if you need something that doesn't stick out and get in the way. Even then, life expectancy is not going to be stellar, depending on usage levels.