On Sat, 18 Feb 2023 12:05:11 +0800
lsg <loushanguan2...@sina.com> wrote:
> Really? i am afraid vmlinuz and initrd pair in iso file don't include
> program that search disk for iso file, as pair in hd-media directory
> does
>
> Debian11.6/main/installer-amd64/current/images/hd-media
>
> though it's possible to boot iso file with grub, but it's too
> complicated
>
> it seems few users are using hard disk installation method theses days
I haven't been entirely clear about what I do. I do boot d-i using
grub. The following should make it a bit less opaque.
root@dti386:~# cat /etc/grub.d/50_netinst
#!/bin/sh
exec tail -n +3 $0
# This file provides an easy way to add custom menu entries. Simply type the
# menu entries you want to add after this comment. Be careful not to change
# the 'exec tail' line above.
menuentry "Install Debian 12 OS (preseeded)" {
set root='hd0,msdos5'
set isofile=/firmware-testing-i386-netinst.iso
insmod part_msdos
insmod loopback
loopback loop (hd0,msdos5)$isofile
linux (loop)/install.386/vmlinuz auto=true file=/media/preseed.cfg
initrd (loop)/install.386/initrd.gz
}
menuentry "Install Debian 12 OS (Expert)" {
set root='hd0,msdos5'
set isofile=/firmware-testing-i386-netinst.iso
insmod part_msdos
insmod loopback
loopback loop (hd0,msdos5)$isofile
linux (loop)/install.386/vmlinuz rescue/enable=true
initrd (loop)/install.386/initrd.gz
}
root@dti386:~#
The key is the loopback module: grub mounts the iso file as a loopback
device, pulls what it needs from the iso file, and goes from there.
Using the loopback facility eliminates the necessity of a separate
initrd and kernel.
The iso file is on /dev/[vs]da5, the first extended partition, with a
FAT file system. The idea is that the main partitions could get badly
mangled, but grub and this partition survive. This gives you a rescue
or re-installation capability without CD-ROMs, USB sticks, etc.
And, yes, these use Testing/Bookworm's weekly build, not Bullseye's.
The same principle applies to Bullseye.
--
Does anybody read signatures any more?
https://charlescurley.com
https://charlescurley.com/blog/
