[Date Prev][Date Next] [Thread Prev][Thread Next] [Date Index] [Thread Index]

Re: how to use boot.img.gz



Hi,

Long Wind wrote:
> /debian/dists/Debian9.4/main/installer-i386/current/images/hd-media
> it's in directory above

Do you mean something like
  http://ftp.debian.org/debian/dists/stretch/main/installer-i386/current/images/hd-media/
?

It seems hardly to be capable of doing anything without the files from
an installation ISO.
  https://www.debian.org/releases/stretch/i386/ch04s03.html.en#usb-copy-easy
says that you first put uncompressed hd-media/boot.img.gz onto an USB stick
(to get an unpartitioned 1 GB stick with FAT filesystem, bleh), then download
a netinst ISO and put it as file into the filesystem on the USB stick.

The strings in "/initrd.gz" look like it can find the ISO image and mount
it in order to use its files.
So the whole image seems to be a USB stick frontend to (small) i386 or amd64
installation ISOs, which meanwhile are ready for USB stick on their own.


> is it possible to create a bootable CD from it?

Rather not. if you mount it as FAT filesystem and look at its content,
there is not much more than a SYSLINUX bootloader, a Linux kernel "/linux",
and two initial ramdisks "/initrd.gz", "/initrdg.gz".

There is no file "isolinux.bin" and no EFI System Partition in boot.img.gz.
So there is no software for the first step of booting from CD, neither for
BIOS nor for EFI.
So even if the necessary files for the second stage of a SYSLINUX bootloader
are present, you'd still need to get ISOLINUX files ("isolinux.bin" and maybe
others) to bridge the gap between BIOS and the second stage of ISOLINUX or
SYSLINUX.

You could pick the missing files from the installation ISO, which you have
to download anyways. Its file /.disk/mkisofs would give you an idea how to
pack up all files as bootable ISO for CD.

But why build a new ISO when you already have downloaded a good one ?


Have a nice day :)

Thomas


Reply to: