Re: Putting It All On a Stick
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
>
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