can I make a usb key , support efi boot & pcbios

[zulinfi]

hi

How can I make a usb to support boot efi or double boot the efi and pcbios?

[mmeyer]

(2016-07-13 13:06)zulinfi Wrote:  hi

How can I make a usb to support boot efi or double boot the efi and pcbios?

I believe the standard solution to this involves creating a hybrid partition table (GPT + MBR on the same disk). I'm thinking you might be able to put GRUB in the MBR (for BIOS iPXE) along with the .EFI iPXE binary inside of an EFI system partition. It definitely wouldn't be pretty.

I haven't personally used iPXE on a UEFI machine yet, so what I said above might be incorrect.

[NiKiZe]

There is no need for a GPT partitiontable to have a usb drive being efi bootable.

Some steps

1. make bin/ipxe.usb
2. cat bin/ipxe.usb > /dev/sdx (the usb device)
3. fdisk /dev/sdX
4. create a new partition, change to partition type 0x0c
5. mkfs.vfat the new partition (partitionnumber should be 1)
6. mount and create EFI/boot directory
7. make bin-x86_64-efi/ipxe.efi
8. copy bin-x86_64-efi/ipxe.efi to EFI/boot/bootx64.efi
9. unmount and sync

And you are ready to go