0

I have seen many people ask similar questions. I might not be picking up the subtle differences, but here goes. I am a PC Tech. I have made a Bootable flash drive with Grub4dos that allows me to boot several versions of acronis, hirens boot cd, parted magic and several other useful tools from iso files. I have been beating my head against the keyboard trying to find a way to do a similar thing in UEFI. I have even seen people say first use grub2 and the chainload grub4dos. How can I make my flash drive work. I would prefer a single drive that would work in Bios and UEFI, but if I have to have 2 drives that's fine too.

edge9001
  • 1
  • I keep two drives, more for convenience of Install. You must use gpt and need the ESP - efi system partition for UEFI and bios_grub for BIOS boot. I only now use gpt for everything. Bootable UEFI USB Key: https://help.ubuntu.com/community/Installation/UEFI-and-BIOS And: http://ubuntuforums.org/showthread.php?t=2213631&p=13262506#post13262506 But issue is flash drive will only boot from /EFI/Boot/bootx64.efi, which I copy my grubx64.efi to and change name. And standard grub needs /EFI/Ubuntu with its files. You can instlal grub with -removeable flag & then it is bootx64.efi. – oldfred Dec 11 '15 at 20:55
  • This is my BIOS version: http://askubuntu.com/questions/388382/multi-partition-multi-os-bootable-usb/388484#388484 But how you boot installer is how install boots. And UEFI grub will only install to ESP on sda. So you have to copy to sdb or whatever flash drive is. – oldfred Dec 11 '15 at 20:58

1 Answers1

0

You certainly can not use GRUB 2 to chainload GRUB4DOS in EFI mode, since GRUB4DOS is a BIOS-mode boot loader, and the EFI version of GRUB 2 can't launch a BIOS-mode boot loader.

GRUB 2, though, does include the ability to access files in an ISO-9660 disk image, so in theory, you should be able to configure it to boot from a collection of .iso files. I've never tried it myself, though. A quick Google search turned up this forum thread that claims to describe how to do this in BIOS mode. Some details might differ in EFI mode, though.

Another way that might work is to use my rEFInd boot manager and its ISO-9660 driver. You can't read .iso files with rEFInd, though, so you'd need to create partitions on your disk and copy the .iso files' contents to those partitions, as in sudo dd if=sourcefile.iso of=/dev/sdd7, assuming the USB flash drive is /dev/sdd and you want to copy sourcefile.iso to its seventh partition. I can't promise that this will work, but there's a good chance it will. Even if it works, of course, it's more awkward than reading from .iso files, since the partitions will be rather inflexible. The advantage of this approach over the GRUB approach is that it will require less mucking about with configuration files, since rEFInd should auto-detect and run the EFI boot loaders on the partitions.

Rod Smith
  • 44,284
  • 7
  • 63
  • 105