Re: GRUB 2 does not show new kernel :(

[shirish]

Hi all,
       Mr. Bean I shutdown the comp. Cold-booted the comp. & waited
for GRUB to kick in. I chainloaded to GRUB 2 ( it shows up as GRUB
version 1.95) and while the entries are there they are not working.
Some things which might give pointer are :-

title           Chainload into GRUB 2
root            (hd0,0)
kernel          /boot/grub/core.img
savedefault

title           Debian GNU/Linux, kernel 2.6.22-6-generic
root            (hd0,0)
kernel          /boot/vmlinuz-2.6.22-6-generic
root=UUID=7eedd8c9-0471-4a63-af65-939402ec5b4e ro quiet splash
initrd          /boot/initrd.img-2.6.22-6-generic
savedefault

title           Debian GNU/Linux, kernel 2.6.22-6-generic (recovery mode)
root            (hd0,0)
kernel          /boot/vmlinuz-2.6.22-6-generic
root=UUID=7eedd8c9-0471-4a63-af65-939402ec5b4e ro single
initrd          /boot/initrd.img-2.6.22-6-generic
savedefault

title           Debian GNU/Linux, kernel memtest86+
root            (hd0,0)
kernel          /boot/memtest86+.bin

Grub legacy

### BEGIN /etc/grub.d/00_header ###
set default=0
set timeout=100
set root=(hd1,1)

### END /etc/grub.d/00_header ###

### BEGIN /etc/grub.d/10_linux ###
menuentry "Debian GNU/Linux, linux 2.6.22-7-generic" {
        linux   (hd1,1)/boot/vmlinuz-2.6.22-7-generic root=/dev/sdb1 ro
        initrd  (hd1,1)/boot/initrd.img-2.6.22-7-generic
}
menuentry "Debian GNU/Linux, linux 2.6.22-7-generic (single-user mode)" {
        linux   (hd1,1)/boot/vmlinuz-2.6.22-7-generic root=/dev/sdb1 ro single
        initrd  (hd1,1)/boot/initrd.img-2.6.22-7-generic
}
menuentry "Debian GNU/Linux, linux 2.6.22-6-generic" {
        linux   (hd1,1)/boot/vmlinuz-2.6.22-6-generic root=/dev/sdb1 ro
        initrd  (hd1,1)/boot/initrd.img-2.6.22-6-generic
}
menuentry "Debian GNU/Linux, linux 2.6.22-6-generic (single-user mode)" {
        linux   (hd1,1)/boot/vmlinuz-2.6.22-6-generic root=/dev/sdb1 ro single
        initrd  (hd1,1)/boot/initrd.img-2.6.22-6-generic
}
### END /etc/grub.d/10_linux ###

### BEGIN /etc/grub.d/20_memtest86+ ###
menuentry "Memory test (memtest86+)" {
        linux   (hd1,1)/boot/memtest86+.bin
}
### END /etc/grub.d/20_memtest86+ ###

Grub 1.95 version

Ok the first thing is GRUB legacy starts at the MBR. from where I
guess it finds which place to jump to the hdd to start booting &
reading stuff . ( IIRC this is called bootstrapping) while the newer
one shows location of the hdd.  The simplest way would be perhaps to
just change something like :-

linux   (hd1,1)/boot/vmlinuz-2.6.22-7-generic root=/dev/sdb1 ro

to

linux   (hd0,0)/boot/vmlinuz-2.6.22-7-generic root=/dev/sdb1 ro

although should root=/dev/sdb1 is good enough or  should it have the
full UUID as given in grub legacy above ?

linux (hd0,0)/boot/vmlinuz-2.6.22-7-generic
root=UUID=7eedd8c9-0471-4a63-af65-939402ec5b4e ro

Would that be the correct way? I ask because ubuntu now uses  UUID labels
https://help.ubuntu.com/community/UsingUUID

I'm sure quite a few of the things which I have asked would be
standard FAQs for the new GRUB. Hopefully Khaled Hosny is also
listening and can add to his list of things if he feels like doing
documentation :)

Another thing I found out is a simple grub-update is able to change
the grub.cfg to its previous state of 444 .  With a simple sudo chmod
was able to change that :)

Lemme know how to proceed & would do accordingly.
--
         Shirish Agarwal
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