u-boot: remove "Factory reset" ?

Werner Almesberger werner at openmoko.org
Sun Feb 10 23:09:50 CET 2008

Hi all,

we've always had the "Factory reset" option in the boot menu, yet its
role may be less than clear, and its practical relevance questionable.

The mechanism was planned as follows:

- if the system boots normally, the parameter "regular_boot" is passed
  on the boot parameter line

- if we do a "factory reset", u-boot does the following:
  - reset the environment to the hard-coded default settings
  - run dynpart
  - boot implicitly without "regular_boot"

User space would then pick up that information, and perform whatever
cleanup seems useful. To make sure the "Factory reset" option isn't
lost if some minor damage happens to the environment, it's hard-coded
in u-boot.

The motivation for all this was the touch screen calibration: when user
space came up for the first time, there was a mandatory touch screen
calibration. If you got that one wrong, the geometry was all twisted,
and it would be virtually impossible to fix this without going in
through USB or serial and deleting the calibration data.

The "Factory reset" would thus provide a means for resolving
configuration errors made through the regular user interface. (The
things one may do from a shell or with DFU are beyond its scope.)

Now, I don't think user space ever picked up that idea, and we might
have eliminated this sort of traps anyway. So the "Factor reset"
probably doesn't serve a real purpose anymore.

This gets particularly confusing with NOR, which is per definition all
about recovery. So I'm inclinded to remove that hard-coded "Factory
reset" from u-boot for GTA01 and GTA02. One could still implement a
slightly less robust equivalent by simply defining another boot menu
item in the u-boot environment.

Any objections ?

- Werner

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