I have a USB installation of Ubuntu. It's a bootable usb drive (but not a Live version, it's a full installation). Its grub is set into BIOS mode, installed on /dev/sdb with the Boot Flag. What can I do to make this same usb stick also bootable on a mac?
Right now, I can boot with it on both BIOS and EFI laptops by simply telling the laptop to "boot from usb" (I don't need specific boot manager or EFI entries, just a manual usb booting each time). Can I do that with the Mac too (without compromising my existing PC-able booting?). Right now, when I boot my EFI macbook pro with that usb stick installation, holding down the Option key, the Mac doesn't recognize it as bootable. It only gives me the internal mac drive option. What could I do to modify my existing installation to make it additionally bootable on a Mac?