[U-Boot] u-boot retries with fallback to other images

[Wolfgang Denk]

Dear Brendan,

In message <5663B74E.7000204 at etrix.com.au> you wrote:
> 
> Is there any documentation or u-boot support for having a list of boot
> images to try, starting with the first in the list, trying 1, 2 or 3
> times, then trying the next in the list.
> 
> e.g. boot kernel at mmcblk0p3, then mmcblk0p2, then mmcblk1p2, then
> tftp/nfs last resort fallback ?
> or
>     boot off partition 3 of eMMC, then partition2 of eMMC, then
> partition 2 of SD card, then tftp/nfs ?

Define a set of boot commands, say bootcmd1, bootcmd2, ...
and then simply do

	run bootcmd1; run bootcmd2; ...

The furst one that succeeds will not return.

Note that the key problem with such a simplistic approach is that it
will not help you in case an image looks OK, but hangs during boot -
in that case, you need a watchdow and support for the bootcount
feature.

Best regards,

Wolfgang Denk

-- 
DENX Software Engineering GmbH,      Managing Director: Wolfgang Denk
HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany
Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd at denx.de
"It is better to have tried and failed than to have  failed  to  try,
but the result's the same."                           - Mike Dennison