[syslinux] FW: boot fails on some system

Jethro Tull
2017-04-14T11:10:04Z

________________________________________
From: Jethro Tull [heavytull at hotmail.com]
Sent: Thursday, April 13, 2017 9:56 PM
To: Ady Ady
Subject: Re: [syslinux] boot fails on some system

On Thu, 13 Apr, 2017, 20:27:03 +0000, Ady Ady via Syslinux
wrote:
>
> > I used syslinux to make an external usb hard drive booting up
"system rescue cd" from a FAT primary partition.
> > The procedure I followed was setting on the boot flag on the FAT
partition and copying the content of the iso image to it and renaming isolinux
to syslinux wherever needed. I then unmounted the device and ran "syslinux
-d /syslinux/ -i /dev/sdxn" where sdxn is the appropriate partition. It
worked nicely on both laptops i have at hand.
> >
> > Then I wanted to try the same using an ext2 partition instead and so
using extlinux. For this, after creating an ext2 partition, moving the boot flag
to it and copying the live linux files, I copied the file mbr.bin from the
syslinux package to the hard drive mbr. Then I ran "extlinux -i
/mnt/mountpoint". This time booting up "system rescue cd" failed
on one of the two laptops. Afterwards even retrying to boot from the FAT
partition resulted with the same computer in failing. I hadn't saved the
initial mbr content, so couldn't restore it, hence mbr.bin should still be
in place and this might be what the failing laptop doesn't like.
> >
>
> (snip)
>
> How _exactly_ did you "copy" (again) the mbr.bin file (and why
again)?
> Which command did you use? Before you executed such command, was the
> filesystem volume mounted or unmounted?
>
> Please post the exact command you used for formatting the FAT volume.
> Please also post the command you used when creating the ext2 volume.
>
> If you repeat the _whole_ initial procedure you described (installing
> mbr.bin, then using FAT and the 'syslinux' installer), can you boot
> then?
>
> Regards,
> Ady.

again? actually for the first test, i.e. booting from the FAT partition I
didn't put mbr.bin to the hard drive's mbr. I just executed the step as
I
described.

I paid attention to mbr.bin only when I started to be interested in bootting
off an ext2/3 partition. And that's because it was mentionned in the
tutorial
I looked at, which this one :
http://www.syslinux.org/wiki/index.php?title=EXTLINUX, and I used the exact
same command i.e. "cat mbr.bin > /dev/sdx" where sdx is the master
device and
while no partition of the device was mounted.

The FAT volume was formatted by gparted. For the ext2 partition I used
'$mke2fs -t ext2 -L "sysrescd" /dev/sdxn'. I always use fdisk
to toggle the
boot flag.

As i said this time the device is failing to boot on one of the two laptops.
Maybe I should have mentionned that it meant the other booted fine for cases
described in my initial email i.e. in the first test with the FAT partition
before paying attention to mbr.bin, in the case of the ext2 partition after
having modified the device's mbr by copying to it mbr.bin as described, and
in the case I reattempted to boot off the FAT partition while the mbr of the
device was modified.