Syslinux - Aug 2019 - Extlinux no longer bootable, how to fix?

Hi,

I'm experiencing a strange problem, my extlinux is no longer bootable,
and I'm wondering how to troubleshoot the problem for a fix.

It's not just an one-off thing, but is happening to me all the time --
I use extlinux to boot up all my linux, and it has always been working
for me, for at least 10+ years. However recently I started to
duplicate my linux system from partition to partition, from a
carefully configured one, and from machine to machine as well.

- during the mirror/transfer, I always exclude the
/boot/extlinux/ldlinux.sys file
- then after the transfer, I always do a extlinux install via

    extlinux --install $new_os_mnt/boot/extlinux

I think this should be enough, however, the strange problem is that it
is not fully working:

- its menu shows up fine but can?t boot /vmlinuz
- after sellecting the menu, it shows ?Loading /vmlinuz...? then
flashed ?failed?, and go back to the menu again.

Here is my extlinux menu:

LABEL LU18R1
        MENU LABEL LUbuntu ^Bionic
        MENU DEFAULT
        KERNEL /vmlinuz
        APPEND initrd=/initrd.img
root=UUID=ad26a5d8-a4ee-42d3-96aa-1f6f0eaa3968 ro net.ifnames=0 --

- the same extlinux config works from the original mirroring source.
- I've made sure the UUID is updated, thought I think it is irrelevant
as it is the loading of /vmlinuz failed.
- I.e., the real problem is loading the /vmlinuz from extlinux

To confirm the situation, I've duplicate my linux system to at least
three HD partitions, and none of them works. However, using the
exactly same steps, when duplicate to my USB key, the system boots up
beautifully. That's why I'm saying that it is a strange problem.

If you are curious how I boot different linux from different partitions,

- I have extlinux booted from the active partition,
- then chain loading into different linux partitions
- the linux system from the mirrored partitions boot up fine, as I can
start them from Grub4dos. Moreover,
- I Install & boot from grub2, and it is OK too. But I really don't
like grub2, and would like to make extlinux work instead.

All in all, the only problem is loading the /vmlinuz from extlinux, as
the chainloading is fine, and the linux system itself boots up fine
too. and I'm wondering how to troubleshoot the problem, and the fix
too.

Thanks

On Sun, Aug 4, 2019 at 6:13 PM Tong Sun via Syslinux
<syslinux at syslinux.org> wrote:
>
> Hi,
>
> I'm experiencing a strange problem, my extlinux is no longer bootable,
> and I'm wondering how to troubleshoot the problem for a fix.
>
> It's not just an one-off thing, but is happening to me all the time --
> I use extlinux to boot up all my linux, and it has always been working
> for me, for at least 10+ years. However recently I started to
> duplicate my linux system from partition to partition, from a
> carefully configured one, and from machine to machine as well.
>
> - during the mirror/transfer, I always exclude the
> /boot/extlinux/ldlinux.sys file
Presumably this is just a file copy and not duplicating things like
the VBR (the first sector of the file system/partition).
> - then after the transfer, I always do a extlinux install via
>
>     extlinux --install $new_os_mnt/boot/extlinux
>
> I think this should be enough, however, the strange problem is that it
> is not fully working:
>
> - its menu shows up fine but can?t boot /vmlinuz
In the context of your shell command, I assume this exists as
"$new_os_mnt/vmlinuz"?  Or did you really want to load
"$new_os_mnt/boot/extlinux/vmlinuz" and should have specified
"vmlinuz"?
> - after sellecting the menu, it shows ?Loading /vmlinuz...? then
> flashed ?failed?, and go back to the menu again.
What is "$new_os_mnt/vmlinuz"?  A real file or a symlink?
> Here is my extlinux menu:
>
> LABEL LU18R1
>         MENU LABEL LUbuntu ^Bionic
>         MENU DEFAULT
>         KERNEL /vmlinuz
>         APPEND initrd=/initrd.img
> root=UUID=ad26a5d8-a4ee-42d3-96aa-1f6f0eaa3968 ro net.ifnames=0 --
>
> - the same extlinux config works from the original mirroring source.
> - I've made sure the UUID is updated, thought I think it is irrelevant
> as it is the loading of /vmlinuz failed.
> - I.e., the real problem is loading the /vmlinuz from extlinux
>
> To confirm the situation, I've duplicate my linux system to at least
> three HD partitions, and none of them works. However, using the
> exactly same steps, when duplicate to my USB key, the system boots up
> beautifully. That's why I'm saying that it is a strange problem.
>
> If you are curious how I boot different linux from different partitions,
>
> - I have extlinux booted from the active partition,
> - then chain loading into different linux partitions
> - the linux system from the mirrored partitions boot up fine, as I can
> start them from Grub4dos. Moreover,
> - I Install & boot from grub2, and it is OK too. But I really don't
> like grub2, and would like to make extlinux work instead.
>
> All in all, the only problem is loading the /vmlinuz from extlinux, as
> the chainloading is fine, and the linux system itself boots up fine
> too. and I'm wondering how to troubleshoot the problem, and the fix
> too.
>
> Thanks
-- 
-Gene

Thanks Gene,

On Mon, Aug 5, 2019 at 7:00 AM Gene Cumm wrote:
>
> On Sun, Aug 4, 2019 at 6:13 PM Tong Sun via Syslinux
> <syslinux at syslinux.org> wrote:
> >
> > I'm experiencing a strange problem, my extlinux is no longer
bootable,
> > and I'm wondering how to troubleshoot the problem for a fix.
> >
> > It's not just an one-off thing, but is happening to me all the
time --
> > I use extlinux to boot up all my linux, and it has always been working
> > for me, for at least 10+ years. However recently I started to
> > duplicate my linux system from partition to partition, from a
> > carefully configured one, and from machine to machine as well.
> >
> > - during the mirror/transfer, I always exclude the
> > /boot/extlinux/ldlinux.sys file
>
> Presumably this is just a file copy and not duplicating things like
> the VBR (the first sector of the file system/partition).
Exactly, only duplicate files via rsync
> > - then after the transfer, I always do a extlinux install via
> >
> >     extlinux --install $new_os_mnt/boot/extlinux
> >
> > I think this should be enough, however, the strange problem is that it
> > is not fully working:
> >
> > - its menu shows up fine but can?t boot /vmlinuz
>
> In the context of your shell command, I assume this exists as
> "$new_os_mnt/vmlinuz"?  Or did you really want to load
> "$new_os_mnt/boot/extlinux/vmlinuz" and should have specified
> "vmlinuz"?
Yes, there is "$new_os_mnt/vmlinuz"; no, there isn't a
"$new_os_mnt/boot/extlinux/vmlinuz".
> > - after sellecting the menu, it shows ?Loading /vmlinuz...? then
> > flashed ?failed?, and go back to the menu again.
>
> What is "$new_os_mnt/vmlinuz"?  A real file or a symlink?
A symlink

/vmlinuz -> boot/vmlinuz-4.15.0-54-generic

As stressed before,

- the same symlink & extlinux config works from the original mirroring
source.
- and I can boot it with Grub4dos
- moreover, I've tried adding another extlinux menu entry that using
directly /boot/vmlinuz-4.15.0-54-generic, but it has the same symptom
as using /vmlinuz as well.
> > Here is my extlinux menu:
> >
> > LABEL LU18R1
> >         MENU LABEL LUbuntu ^Bionic
> >         MENU DEFAULT
> >         KERNEL /vmlinuz
> >         APPEND initrd=/initrd.img
> > root=UUID=ad26a5d8-a4ee-42d3-96aa-1f6f0eaa3968 ro net.ifnames=0 --
> >
> > - the same extlinux config works from the original mirroring source.
> > - I've made sure the UUID is updated, thought I think it is
irrelevant
> > as it is the loading of /vmlinuz failed.
> > - I.e., the real problem is loading the /vmlinuz from extlinux
> >
> > To confirm the situation, I've duplicate my linux system to at
least
> > three HD partitions, and none of them works. However, using the
> > exactly same steps, when duplicate to my USB key, the system boots up
> > beautifully. That's why I'm saying that it is a strange
problem.
> >
> > If you are curious how I boot different linux from different
partitions,
> >
> > - I have extlinux booted from the active partition,
> > - then chain loading into different linux partitions
> > - the linux system from the mirrored partitions boot up fine, as I can
> > start them from Grub4dos. Moreover,
> > - I Install & boot from grub2, and it is OK too. But I really
don't
> > like grub2, and would like to make extlinux work instead.
> >
> > All in all, the only problem is loading the /vmlinuz from extlinux, as
> > the chainloading is fine, and the linux system itself boots up fine
> > too. and I'm wondering how to troubleshoot the problem, and the
fix
> > too.
> >
> > Thanks
>
> --
> -Gene

> 
> - its menu shows up fine but can?t boot /vmlinuz
> - after sellecting the menu, it shows ?Loading /vmlinuz...? then
> flashed ?failed?, and go back to the menu again.
> 
> Here is my extlinux menu:
> 
> LABEL LU18R1
>         MENU LABEL LUbuntu ^Bionic
>         MENU DEFAULT
>         KERNEL /vmlinuz
>         APPEND initrd=/initrd.img
> root=UUID=ad26a5d8-a4ee-42d3-96aa-1f6f0eaa3968 ro net.ifnames=0 --
> 
> - the same extlinux config works from the original mirroring source. -
> I've made sure the UUID is updated, thought I think it is irrelevant as
> it is the loading of /vmlinuz failed. - I.e., the real problem is
> loading the /vmlinuz from extlinux
> 
> To confirm the situation, I've duplicate my linux system to at least
> three HD partitions, and none of them works. However, using the exactly
> same steps, when duplicate to my USB key, the system boots up
> beautifully. That's why I'm saying that it is a strange problem.
 
 
There are several things to try. Let's start for the simplest.

In your EXTLINUX config file, instead of using:

KERNEL /vmlinuz

try changing it to:

LINUX /vmlinuz

Then, when you get to the boot menu, exit the menu and get to the boot 
prompt instead (by pressing [Esc], more than once if needed).

Then, from the boot prompt, type in:

LU18R1

which is the label you are using. Press [Enter].

With this minimal changes, are you seeing the same exact behavior as 
before? Are the resulting messages the same as before? Any additional 
clue?

If this is not enough, I would suggest carefully reading the 
"Filesystem" wiki page in the Syslinux wiki. This is just a
"hunch"
(based on some "clues" in your email, although you have not explicitly
mentioned the filesystems that you are using for the bootloader in your 
HDD nor for the USB device).

If the wiki page doesn't give you any clues either, we'll see how to 
proceed then, depending on your report(s). There are several more 
things to troubleshoot, if required.

Regards,
Ady.