I discovered that using a GPT partition scheme meant that my stick wouldn’t work with older systems, which is a shame because I had a partition for using like a regular USB stick which is useful for transferring files around.

As it happens you can have disks that are both GPT and MBR, as detailed at http://www.rodsbooks.com/gdisk/hybrid.html (note that that guide is written by Rod Smith, the maintainer of rEFInd mentioned is my last post on this, and also gdisk, which I used for making hybrid MBRs before I realised it was also one of the things iPartition could do).

Another thought I had was: what about these news PCs that will be using UEFI (an updated and more standardised EFI)? I have some theories about being able to put the right file (say /efi/boot/bootx64.efi, which is a standard fallback location) in a partition by itself, with bootx64.efi being a GRUB EFI application made to use my existing HFS+ partition for it’s modules. Unfortunately I haven’t got any computers to test this on.