On Thu, 16 Feb 2006 ian.ridge@apdcomms.com wrote:

Power disconnect during firmware update:

We are implementing facility for automatic firmware upgrades (either the Linux uImage or cramfs) on our embedded device. However there is a requirement that the device is not broken by (the user for example) disconnecting the power supply at any stage during the flash update.

In the absence of a backup battery, I guess the boot loader would have to be modified to cope with this. Has anybody produced a solution already?

If not I'm considering adding a command to u-boot. 'update' could work as follows:

[SNIP]

Any comments?

Just to make sure you're considering all options -- the problem could also be addressed solely with Linux.

Filesystem upgrades were discussed in a paper at the 2005 Linux Symposium (URL not at hand but easy to find), I think from codefidence.com .

kexec() seems to be the current recommendation for kernel upgrades, though I think it's only in 2.6.

Further discussion of approaches not involving U-Boot would be off-topic here, of course.

Tom Ziomek