Re: Failsafe bootloader

In message [ref] you wrote:

A few of the added requirements on top of that are:
1) The target shall boot up in the old kernel, if a bogus kernel is loaded

Define "bogus kernel"! Depending if you mean one which was  corrupted
during  download/installation  you can use a checkum; if you mean one
which fails to start the application you can use a watchdog.

Both is trivial and supporeted by several bootloaders.

2) The target shall boot up in the old application, if a bogus
	application is loaded

Same as above. Here it comes handy if you don't have  to  bundle  the
application with the kernel into one image.

3) On the management side an update shall be handled as a single file,
	the target may decide to 'unpack' it when received.

OK, not too difficult.

We have looked all over the net, but none of the bootloaders found
so far could meet the above demands.

Ummm... how comes you missed to look into U-Boot? It easily  performs
all your reqirements. Without modifying a single line of code.

The boot loaders usually have an interactive mode used to select
between different configurations - and there are no feedback from
the application side if the reboot actually went well.
The interactiviness does not fit well with an embedded target.

U-Boot allows for canned command sequences and even shell scripts.

Do you know of a boot loader that partially or fully meets the above
requirements?

U-Boot meets your rrequirements fully (and some more :-)

Today we are using VxWorks - for which we have made our own boot loader.
The boot laoder allows the boot loader itself, and the application part
to be upgraded - and if a restart is failed the old version will
be activated on a subsequent build.
I want the same behaviour in the Linux based target.

==> http://sourceforge.net/projects/u-boot

See also: http://www.denx.de/re/DPLG.html

If you have questions, send an email to the u-boot-users mailing list
(or to me).

Best regards,

Wolfgang Denk

--
Software Engineering:  Embedded and Realtime Systems,  Embedded Linux
Phone: (+49)-8142-4596-87  Fax: (+49)-8142-4596-88  Email: wd@denx.de
Bus error -- please leave by the rear door.

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