Pop!_OS includes a built-in "recovery" partition that you can use if your system fails to boot. Join me as I demonstrate how to access your installed system, perform maintenance on your package manager, and reinstall your bootloader from within the recovery partition.
Use the Recovery Partition: https://support.system76.com/articles/pop-recovery/
Fix Package Manager Issues: https://support.system76.com/articles/package-manager/
Repair the Bootloader: https://support.system76.com/articles/bootloader/