Question about .altboot

QNX Newsgroups (Archives) qdn.public.qnxrtp.newuser
1

I know that I can reboot with the .altboot file by using the escape key at
the proper time, but can I configure the boot loader to automatically boot
from the .altboot file if the .boot image is corrupt?

Thanks,
David Kuechenmeister
david.kuechenmeister@viasat.com

2

You could rebuild the image, see ‘mkifs’ utility. Also you already have build files
‘qnxbasedma.build’ and ‘qnxbase.build’ (sorry if I don’t remember right the names, just look at
/boot directory - you’ll find all you need).

To quick fix - just copy .altboot file over .boot (you must be root). Boot loader always look for
…boot file if esc key was not pressed and for .altboot if esc key was pressed. You can creat your
own image and overwrite .boot, but you always will have reserve .altboot to avoid the result of
misstakes in own image. So, keep always good image in .altboot and you’ll never have to use floppy
in order to boot system :wink:

Eduard.
ed1k at ukr dot net

David Kuechenmeister <david.kuechenmeister@viasat.com> wrote in article
<acao1k$8i6$1@nntp.qnx.com>…

I know that I can reboot with the .altboot file by using the escape key at
the proper time, but can I configure the boot loader to automatically boot
from the .altboot file if the .boot image is corrupt?

Thanks,
David Kuechenmeister
david.kuechenmeister@viasat.com

3

I appreciate the help. I’m looking for a way to let the bootloader select
the altboot file without any user interaction. The situation that I’m trying
to salvage is that of a faulty boot file load to a device in a remote
location. I’d like to have the system automatically degrade to a known good
image that I’ve stored in altboot. Comments that I have read in these
newsgroups indicate the boot loader is fairly limited, but I haven’t been
able to find any documentation on its function.

Thanks again for any help that you might be able to provide.

David Kuechenmeister
david.kuechenmeister@viasat.com



“ed1k” <ed1k@spamerstrap.com> wrote in message
news:01c1fff9$b8be3fa0$106fa8c0@ED1K…

You could rebuild the image, see ‘mkifs’ utility. Also you already have
build files
‘qnxbasedma.build’ and ‘qnxbase.build’ (sorry if I don’t remember right
the names, just look at
/boot directory - you’ll find all you need).

To quick fix - just copy .altboot file over .boot (you must be root). Boot
loader always look for
.boot file if esc key was not pressed and for .altboot if esc key was
pressed. You can creat your
own image and overwrite .boot, but you always will have reserve .altboot
to avoid the result of
misstakes in own image. So, keep always good image in .altboot and you’ll
never have to use floppy
in order to boot system > :wink:

Eduard.
ed1k at ukr dot net

David Kuechenmeister <> david.kuechenmeister@viasat.com> > wrote in article
acao1k$8i6$> 1@nntp.qnx.com> >…
I know that I can reboot with the .altboot file by using the escape key
at
the proper time, but can I configure the boot loader to automatically
boot
from the .altboot file if the .boot image is corrupt?

Thanks,
David Kuechenmeister
david.kuechenmeister@viasat.com

4

David Kuechenmeister <david.kuechenmeister@viasat.com> wrote in article
<acat88$c85$1@nntp.qnx.com>…

I appreciate the help. I’m looking for a way to let the bootloader select
the altboot file without any user interaction. The situation that I’m trying
to salvage is that of a faulty boot file load to a device in a remote
location. I’d like to have the system automatically degrade to a known good
image that I’ve stored in altboot.

But which criterion to know about image integrity do you mean?

Comments that I have read in these
newsgroups indicate the boot loader is fairly limited,

Yes, because it placed in an bootsector (it’s only 512 bytes). You could write you own loader,
which will meet your requirements, look at “Building Embedded Systems” documentation, “Writing IPL”
section. For example, you could to calculate the CRC of image before to pass control to it, or do
some other trick… It’s very system depended thing… the way to paranoia… what’s about the boot
loader is damaged?

Good luck!

Eduard.
ed1k at ukr dot net


but I haven’t been
able to find any documentation on its function.

Thanks again for any help that you might be able to provide.

David Kuechenmeister
david.kuechenmeister@viasat.com

5

Hello,

“ed1k” <ed1k@spamerstrap.com> wrote in message
news:01c20008$0108fda0$106fa8c0@ED1K…

David Kuechenmeister <> david.kuechenmeister@viasat.com> > wrote in article
acat88$c85$> 1@nntp.qnx.com> >…
I appreciate the help. I’m looking for a way to let the bootloader
select
the altboot file without any user interaction. The situation that I’m
trying
to salvage is that of a faulty boot file load to a device in a remote
location. I’d like to have the system automatically degrade to a known
good
image that I’ve stored in altboot.

section. For example, you could to calculate the CRC of image before to
pass control to it, or do
some other trick… It’s very system depended thing… the way to
paranoia… what’s about the boot

I don’t think David meant a corrupt boot image alone, but rather a faulty

…boot image (i.e. one that
won’t come past some point where the system is running).

It would indeed be very nice if a flag could be set that tells the
bootloader to use .altboot on the next
boot attempt.

You would probably also need a watchdog to reset the machine, though, for
the system David decribes.

Regards,

Leon.