Depending on the Puppy version.
Most Puppy versions have two boot loaders, provided in their ISO.
One for UEFI type bios booting.
One for legacy type bios booting.
If booting Puppy version you installed on a USB stick.
The stick may show as two different USB devices, to select to boot from.
Select to use the correct one, for the type of bios, the computer is using.
Example:
I installed BookwormPup64 10.0.10 on the USB stick as live install. (all that is in the ISO is on the stick)
The computer I am using, can see the USB stick as two completely, different drives.
One is identified as a UEFI boot device.
One is identified as a legacy bios boot device.
If I pick the UEFI identified USB device, it boots for a UEFI bios setup.
It's displayed boot menu entries, all work for UEFI bios booting.
If I pick the legacy bios identified USB device, it boots for that type bios.
A completely different boot menu listing is displayed.
If you have a UEFI bios setup to boot in legacy or CSM mode.
Which one you choose, is up to how this bios handles, that way to run.
But one or both should work.
