I installed POP! OS on my laptop a few days ago but secure boot wont let me boot it. I cant disable secure boot or UEFI mode because after installing a bios update my BIOS setup menu wont open anymore. Its a bug and many similar models have it. My bios is read write protected so I cant install a old version of it either. I have heard that Ubuntu and some other popular OSes use a small bootloader known as shim to boot the main bootloader. How can I achieve this on POP! OS?
I was able to setup Secure boot on Pop OS using PreLoader. As always arch wiki has a great explanation how to set it up.
After installing pop OS don't reboot but mount your EFI partition. Download PreLoader and Hashtool https://blog.hansenpartnership.com/linux-foundation-secure-boot-system-released/ Then copy preloader and hashtool to the /efi/EFI/systemd. Finally rename systemd-bootx64.efi to loader.efi and create another copy of preloader and name it systemd-bootx64.efi (this is for allowing EFI to boot straight to preloader without creating a new UEFI entry).
After this enjoy the Pop OS. Sometimes after Kernel update your system would boot to prelaoder where you will have to accept the new hash. But most of the time your system would boot straight to pop os.
Hope it helps!