Dear Alexandre,
In message 1822628084.945501.1364317027872.JavaMail.root@openwide.fr you wrote:
In fact I would like to keep the bootcount value after a shutdown to handle update failures. Some embedded systems have only network access for administration and if you install an updated system with a misconfiguration of the network interface, you can't access anymore to the machine and you can't reset it. So the only way to reset the device is to unplug and replug but bootcount value is reset... So you can't switch back to a safe system...
You can define your own mechanism to do something like that, but please do not misuse the bootcount for something it was never meant for. The bootcount is defined to count the number of boots after power on; i. e. when you power on a board, the boot counter must by definition start with the value zero.
If you move the bootcount into a non-volatile memory, you add a history to the process and breaks this assumption.
That's why I suggest to use an environment variable (and may be a configuration option) to enable/disable this features.
It should be easy and straightforward to implement such a feature by defining a new environment variable. All this can be done using standard scripting, i. e. you do not need any code changes and thus no new config options.
Best regards,
Wolfgang Denk