Ubuntu server 20.04 installation failed: non system disk error

[briant789]

Laptop is a HP probook 6540b.

[oldfred]

Looks like it may be a very early UEFI based system.
But for those, generally a BIOS install just works.

Do you have some setting in UEFI/BIOS on boot mode.
Is it the most current UEFI, but still probably pretty old.
Some HP needed UEFI/BIOS settings. See if any of these apply as vendors often do similar settings across multiple models. And look for others that relate to boot mode or drive.
HP Elitebook 840 G5 gpt issues -
HP put a fail-safe gpt recovery into the UEFI Settings, go into the UEFI Menu in Security -> Hard Drive Utilities -> Uncheck "Save/restore GPT System of Hard Drive"
https://ubuntuforums.org/showthread.php?t=2436271
HP Check if Customized UEFI settings available like this HP ProBook 4340
https://ubuntuforums.org/showthread....6#post13527216

[briant789]

There is no secure boot option in my bios. I also tried to see if there is a bios update available from HP for a probook 6450b, but no.
I see one setting where I can check / uncheck UEFI Boot Mode. Tried both options, no result.

[CelticWarrior]

Secure Boot settings should be at Security.
If Legacy is selected it's very likely that setting won't show up because not applicable.