Re: Dedicated grub2 partition

[Goh Lip]

On Wednesday 06,October,2010 07:29 AM, Barry Jackson wrote:
> Hi Goh,
> No joy yet :-(
>
> I have currently 4 test entries which I am now numbering to keep track :-
> menuentry 'Test 1' {
>    loopback loop (hd0,1)/pclinuxos-lxde-2010.1.iso
>    linux (loop)/isolinux/vmlinuz findiso=/pclinuxos-lxde-2010.1.iso
> boot=boot quiet  noeject noprompt
>    initrd (loop)/isolinux/initrd.gz
> }
>
> menuentry 'Test 2' {
> loopback loop (hd0,1)/pclinuxos-lxde-2010.1.iso
> linux (loop)/isolinux/vmlinuz findiso=/pclinuxos-lxde-2010.1.iso
> boot=live quiet noeject noprompt
> initrd (loop)/isolinux/initrd.gz
> }
>
> menuentry 'Test 3' {
> loopback loop (hd0,1)/pclinuxos-lxde-2010.1.iso
> linux (loop)/isolinux/vmlinuz boot=isolinux vga=788 fromusb
> root=/dev/sda1  acpi=on fstab=rw,noauto
> initrd (loop)/isolinux/initrd.gz
> }
>
> menuentry 'Test 4' {
> loopback loop (hd0,1)/pclinuxos-lxde-2010.1.iso
> linux (loop)/isolinux/vmlinuz
> isofrom=/dev/sda1/pclinuxos-lxde-2010.1.iso boot=live quiet noeject
> noprompt
> initrd (loop)/isolinux/initrd.gz
> }
> Tests 1,2,and 4 all produce the same kernel panic at the start of boot
> when trying to run the initrd.
> http://i115.photobucket.com/albums/n287/barjac_2006/DCP_3424.jpg
>
> Test 3 runs the initrd fine until it tries to access livecd.sqfs and
> fails to find it on a real device.
> http://i115.photobucket.com/albums/n287/barjac_2006/DCP_3422.jpg
>
> Sorry about the bad photos.
>
> Barry


Hi Barry, I was about to give up when I saw "fromusb" in the 'test 3' 
and that 'worked somewhat' up to the point of not finding the loop. Your 
fairly good pics show sda, sdb and sdc.

Your iso file is not in the usb disk, right? (you said it is in sda1 
root partition). Please help me understand why the "fromusb' was added 
in, and if this is from the old line to boot the extracted sqsfs file, 
was this extracted to the usb as well?

To jump the gun if it is the usb, using (hd0,x) and /dev/sdax for 
booting usb and indeed other than primary hard disk is fraught with 
errors (by bios, not uefi). It is best to use
"search --xxxxxxxxxxxxxxxx" and avoid (hd0,x)
Also avoid using "=/dev/sdax  and use.... oh boy, don't think we can use 
label or uuid here; that's why 'findiso' replaces 'isofrom=/dev/sdax" 
but the problem is sometimes 'findiso' doesn't work with some livecd's.


Let's see...we can, at grub prompt, do a
ls
<check which is the usb entry>
say, if it is really (hd0,1), then
ls (hd0,1)
<and check if it is sda1 or sdb1 or sdc1,
then modify the 'isofrom=/dev/sdyx/ ...." to the correct y and x>

Barry, note that this might change with next boot up.
ie., usb disk may become (hd2,1) instead or /dev/sdb1

Oh, if it is not on the usb, and the usb and external drives are not 
required, lets, pull out all these disks so that it doesn't mess up the 
boot.


Seriously, Barry, I was about to give up. Have been raking my brains 
out. Nowadays, I only boot up iso (casper) for those 'pre-release' OS to 
test out and had been installing even those "alpha 3's" (by then, fairly 
okay) to disk. - reason being kernel changes cannot be made persistent- 
(there are ways, but too complicated to bother with). And grml, 
rescuecd, gparted, grubcd is made obsolete by my "lubuntu-on-the-stick".

Regards - Goh Lip

ps; like your tenacity  :)