sneaky dual-boot

sneaky dual-boot

While the combination of BIOS boot and GPT is technically feasible it's notexactly standard, I'm not sure if grub supports it or if a hybrid partion table (which is it's own can of worms) is needed.

GRUB supports booting from a GPT disk in BIOS mode, but you will need an extra BIOS boot partition. A disk with an MBR partition table usually contains a gap between the boot record and the first partition, which GRUB takes advantage of. GPT-partitioned disks do not (typically) have this "no man's land", so a separate partition is used instead. Using a partition is cleaner anyway, and GPT also does not have a practical limit on the number of partitions a disk can contain, so one extra partition doesn't make a big difference.