Thanks for the A2A.
You don’t! It’s as simple as that.
You can only use ONE partitioning scheme on a drive, not two. You can either use GPT or MBR, but not both.
You can use them on separate drives. But not on the same. Because a) it’s not necessary and b) it’s poor management. The operating system always has to be adjusted for the architecture. Operating systems are meant to be used with ONE device and not many.
Legacy BIOS and UEFI use two different boot processes. BIOS uses a boot loader in the header of the storage space and UEFI searches for a .efi file on a FAT32 partition. It doesn’t make sense to use both at the same time. Not only would you need a BIOS that supports both. You would need to constantly change the according setting in your BIOS. That’s just tedious.
Short and sweet: YOU DON’T!
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