[syslinux] help booting iso's?
James Miller
gajs-f0el at dea.spamcon.org
Fri Jul 6 12:08:55 PDT 2018
Hi. I prefer using the syslinux boot loader and recently undertook a
project of creating a multiboot USB drive that boots using syslinux. The
aim is to create a medium from which various live linux environments can
be run for things like system maintenance, installation, and perhaps
demonstration. I anticipate using this multiboot USB drive on mostly
legacy, BIOS systems, if that matters.
As many syslinux users would likely anticipate, some iso image files I've
tested boot just fine using memdisk. For some other iso's, I found some
directives on the web that advise loop-mounting the iso's, copying over to
the multiboot USB certain files and folders, and crafting applicable
syslinux.cfg stanzas. I've managed get a few more live environments
booting already via those methods. But, since not all live-environment
iso's are constructed in the same way, not all are readily susceptible to
the same sorts of directives. One case in point is the Void Linux iso.
I'd first like to ask about something that was suggested as a possible
solution but about which I could find no documentation. I was led to
believe that it would be possible, using syslinux, to boot an iso image
located within a partition by somehow specifying its address on disk. I
see nothing in syslinux documentation, guidelines, or forum postings, that
suggests that this is really possible. So, am I correct in assuming that
the individual who suggested that is just plain wrong?
In order to succeed in booting into the the Void live environment the iso
provides, what I wound up doing is creating some appropriately-sized
partitions on my USB drive and dd'ing the iso image to one of them (I
created an extended partition and included within it 6 logical
partitions). I'd understood that syslinux would be capable of booting such
a partition, and there even seem to be official directives on doing that
sort of thing. But nothing I have tried so far will allow me, using
syslinux, to boot the iso dd'd to that partition--regardless of whether I
specify in the syslinux.cfg entry the address of the iso's mbr, or the
partition's location (e.g., hd0, 5).
One point of confusion I have is how to specify the drive that syslinux is
booted from, and thus the one on which the dd'd partition is located: it
being a USB drive rather than the computer's hard drive, perhaps hd0 is
not the correct specifier? Can anyone offer clarification on that issue?
Incidentally, I recently put grub4dos on this USB drive, since I'd
understood it was more capable when it comes to booting iso's. Since it
was already present, I decided, using a syslinux menu item that would
invoke grub4dos, to try booting the partition with it. And, with an
appropriate menu.lst item, the partition does, in fact, boot this way. The
relevant entry is:
title Boot Void 64-bit dd'd to 1st logical partition
map --heads=0 --sectors-per-track=0 (hd0,4)0+716800 (0xff)
map --hook
chainloader (0xff)
Any assistance in getting such partitions to boot using syslinux will be
much appreciated. Thanks.
PS Various syslinux.cfg entries I've tested in my attempts to boot the
partition straight from the syslinux menu:
LABEL Void linux 64
MENU LABEL Void Linux x86_64
COM32 chain.c32
APPEND mbr:0x2addfccb
LABEL Void linux 64
MENU LABEL Void Linux x86_64
COM32 chain.c32
APPEND hd0 5
LABEL Void linux 64
MENU LABEL Void Linux x86_64
COM32 chain.c32 mbr=0x2addfccb
LABEL Void linux 64
MENU LABEL Void Linux x86_64
COM32 chain.c32 hd0, 5
LABEL Void linux 64
MENU LABEL Void Linux x86_64
COM32 chain.c32
APPEND hd1 5
# being unsure whether I'd specified correctly the USB drive as hd0
More information about the Syslinux
mailing list