pearOS won't boot / installer won't start with Secure Boot enabled

pearOS's bootloaders (Ploader on the live USB, GRUB on the installed system) aren't signed for Secure Boot - there's no shim/MOK enrollment shipped.

Fix: disable Secure Boot in your PC's UEFI/BIOS settings before booting the pearOS USB or after installing.

How to get there varies by manufacturer, but it's usually: reboot, spam Del, F2 or F10 during boot to enter UEFI setup, then look under a Boot or Security tab for Secure Boot and set it to Disabled.

On dual-boot machines, disabling Secure Boot won't stop Windows from booting - Windows works fine with it off, it's just no longer enforced.