Re: Failsafe bootloader

Check out U-Boot
   http://sourceforge.net/projects/u-boot
The project page on sourceforge is pretty much non-existant other than the
CVS link.  Pull down the source -- there _is_ a good README file in it that
explains a lot about u-boot.
   http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/u-boot/u-boot/README?rev=1.30
Wolfgang Denk of Denx Computer Systems runs the project.  He doesn't appear
to have anything on U-Boot on his web site either.
   http://www.denx.de/

The predecessor was ppcboot, which at least has a home page on sourceforge
   http://ppcboot.sourceforge.net/
Pretty much everything said for ppcboot goes for u-boot as well, only
better :-).

U-boot has some scripting capabilities as well as variables that can be
used for rudimentary decision making.  I'm sure Wolfgang will welcome
improvements to the scripting :-).

The scripts can be accessed remotely or via your application (assuming your
application's "failure" mode is sufficient to allow it to write to
flash/eeprom to change the script to a backup mode).  You don't tell us
_how_ the application fails and how it and/or the boot loader is expected
to recover from that failure, so I cannot give you and direct suggestions.

gvb


At 09:28 PM 6/3/2003 -0400, sam@ravnborg.org wrote:

Hi all.

We are developing an application for an embedded target that will be
located in some rural areas. We foresee a need to update the target
with a new version of the application or a new kernel from time to time.

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
2) The target shall boot up in the old application, if a bogus
        application is loaded
3) On the management side an update shall be handled as a single file,
        the target may decide to 'unpack' it when received.

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

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

Background information
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.

        Thanks in advance,

        Sam

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