Dev-mode allows booting self-signed kernels by default.

When you enter dev-mode,

  Pressing Ctrl-U to boot from USB is DISABLED.
  Booting any self-signed kernel from the SSD is ENABLED.

This replaces the "crossystem dev_boot_custom" argument with
"crossystem dev_boot_signed_only", which has the opposite polarity.
So if you want to dev-mode to only boot official kernels, you have to
explictly set it that way. If you leave dev-mode and then come back,
it will go back to the conditions shown above.

BUG=chrome-os-partner:5954
TEST=manual

Just run the factory flow. It was broken; this should fix it (except for any
workarounds that were added while it was broken; those may need to be
reverted).

Change-Id: I13e0edbc0e77c5d6ea609dabf771085006cd1805
Reviewed-on: https://gerrit.chromium.org/gerrit/11853
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Tested-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
9 files changed