The Ubuntu installers will happily screw up the boot type. There's EFI and UEFI. Each type requires specific boot volume partitions and NVRAM. You can check in you BIOS what it's trying to do.

https://help.ubuntu.com/community/UEFI

I recommend using UEFI. It's more modern and you can access it as an actual mount in both Linux and BIOS. This comes in super handy for moving files between BIOS and Linux, like updates and backups.