Then, you can install GRUB for UEFI with: The GRUB configuration (-boot-directory) can be kept in the same place.įirst, you need to mount the EFI system partition and the data partition of your USB drive. You can now install GRUB to support both EFI + GPT and BIOS + GPT/MBR. Recovery/transformation command (? for help): xįinal checks complete. Place EFI GPT (0圎E) partition first in MBR (good for GRUB)? (Y/N): NĬreating entry for GPT partition #1 (MBR partition #1)Ĭreating entry for GPT partition #2 (MBR partition #2)Ĭreating entry for GPT partition #3 (MBR partition #3) Type from one to three GPT partition numbers, separated by spaces, to be added to the hybrid MBR, in sequence: 1 2 3 Just hit the Enter key at the below prompt and your MBR partition table will WARNING! Hybrid MBRs are flaky and dangerous! If you decide not to use one, Recovery/transformation command (? for help): h Hybrid MBR partition table creation example using gdisk: It will not find the partitions it expects to find. Without it, a BIOS MBR based system will not boot. Next you must create a hybrid MBR partition table. This partition can take up the rest of the space of your drive. Your data partition (use a filesystem supported by GRUB).This partition can be as small as 50 MiB. An EFI System partition (gdisk type code EF00 with a FAT32 filesystem).A BIOS boot partition (gdisk type code EF02).This configuration is useful for creating a universal USB key, bootable everywhere.įirst of all you must create a GPT partition table on your device. # grub-install -target=x86_64-efi -removable -boot-directory=/mnt/boot -efi-directory=/mntįor UEFI, the partition has to be the first one in an MBR partition table and formatted with FAT32. In case you want to boot ISOs in UEFI mode, you have to install grub for the UEFI target: # grub-install -target=i386-pc -recheck -boot-directory=/mnt/boot /dev/sdX Mount the filesystem located on the USB drive: Choose the size based on the total size of the ISO files that you want to store on the drive, and plan for extra space for the bootloader. See Partitioning and File systems#Create a file system. Reason: How much extra space is needed for the bootloader? (Discuss in Talk:Multiboot USB drive)Ĭreate at least one partition and a filesystem supported by GRUB on the USB drive.

Ventoy grub command line