Fascinating stuff. The one thing I forgot is cp and dd are not the same. Now, does this mean I should run the ISO I made with Jigdo through isohybrid now that I have a running Linux system?
On Thu, 31 Dec 2015 17:25:39 +0100, you wrote: >Hi, > >Steve Matzura: >> Thomas, just dd the file? That really works? > >Yes. It's called "isohybrid". > http://www.syslinux.org/wiki/index.php/Isohybrid > >As said: Copy it onto the base device, the whole "disk". >It must overwrite MBR, partition table, GPT, whatever partitioning >and boot sector is present on the disk. > >Common mistakes are to copy it as data file into a file system, >or as filesystem image into a partition of the "disk". > > >> I've heard of this being the way to do things, but find it hard to >> understand how it could work. I suppose the boot loaders know what to >> do with ISO images. > >It is an interesting adventure to boot on as many systems as possible: >{ BIOS, EFI, Mac firmware, ... } x { Hard disk/USB stick, CD/DVD/BD } > >MBR x86 boot code at the start of the ISO image brings you to >the file > > /isolinux/isolinux.bin > >in the ISO image, where CD booting would start too. > >The MBR bears a partition table. Partition 1 has the >"bootable/active" flag for stubborn BIOSes which would not >boot without it. Partition 2 is the EFI System Partition: > > $ /sbin/fdisk -l debian-8.2.0-amd64-BD-1.iso > ... > Device Boot Start End Sectors Size Id Type > debian-8.2.0-amd64-BD-1.iso1 * 0 43859651 43859652 20.9G 0 Empty > debian-8.2.0-amd64-BD-1.iso2 75632 76463 832 416K ef EFI > (FAT-12/16/32) > >Because SYSLINUX does not boot from CD via EFI firmware, >the EFI equipment is of GRUB2. >If you mount the ISO > > # mkdir /mnt/iso > # mount -o loop debian-8.2.0-amd64-BD-1.iso /mnt/iso > >then you can mount the EFI System Partition as FAT filesystem > > # mkdir /mnt/fat > # mount -o loop /mnt/iso/boot/grub/efi.img /mnt/fat > >and see > > # ls -l /mnt/fat/efi/boot/bootx64.efi > -rwxr-xr-x 1 root root 392192 Sep 6 11:14 /mnt/fat/efi/boot/bootx64.efi > >This file brings you from EFI to the GRUB2 configuration in > /mnt/iso/boot/grub > >For certain old x86 Macs there may be even a HFS+ filesystem >with blessings and all. debian-cd does not do this. But Fedora >LiveCD has HFS+. >The result from grub-mkrescue has HFS+ too. It uses GRUB2 for >both, BIOS and EFI. > >Debian just has an Apple Partition Map entry which points to >the EFI System Partition. (I would really like to know whether >this is of any paractical use.) > > >Have a nice day :) > >Thomas >
