Possible CL here:

https://chromium-review.googlesource.com/c/chromiumos/platform2/+/777687

I'm not sure what we should do when key-id is empty. Apparently we cannot tell the signer not to sign something (it just uses the default key?). I'm not sure why, though. It seems like I should be able to leave a model out of the signer_config.csv file and it should skip it?

Found the other bug

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform2/+/8ea7eb087fd43e895dd75fe68b7edf52da769001

commit 8ea7eb087fd43e895dd75fe68b7edf52da769001
Author: Simon Glass <sjg@chromium.org>
Date: Sun Nov 19 17:39:48 2017

chromeos-config: Allow disabling of firmware for a model

Sometimes a model does not have valid firmware, or it has firmware but the
signer has no key.

Add a new 'no-firmware' property which tells pack_firmware not to include
a model in the firmware update for a build.

This CL is entirely within chromeos-config since the firmware packer gets
all its instructions from libcros_config_host now.

BUG= chromium:786519 
TEST=FEATURES=test sudo -E emerge --nodeps  chromeos-config-host

Change-Id: Iba01c926d27613aaa04765bfed43b3cd4bac5cab
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/777687
Tested-by: Jason Clinton <jclinton@chromium.org>
Reviewed-by: Jason Clinton <jclinton@chromium.org>

[modify] https://crrev.com/8ea7eb087fd43e895dd75fe68b7edf52da769001/chromeos-config/libcros_config/test.dts
[modify] https://crrev.com/8ea7eb087fd43e895dd75fe68b7edf52da769001/chromeos-config/cros_config_host/validate_schema.py
[modify] https://crrev.com/8ea7eb087fd43e895dd75fe68b7edf52da769001/chromeos-config/cros_config_host/validate_config_unittest.py
[modify] https://crrev.com/8ea7eb087fd43e895dd75fe68b7edf52da769001/chromeos-config/cros_config_host/libcros_config_host_unittest.py
[modify] https://crrev.com/8ea7eb087fd43e895dd75fe68b7edf52da769001/chromeos-config/cros_config_host/libcros_config_host.py
[modify] https://crrev.com/8ea7eb087fd43e895dd75fe68b7edf52da769001/chromeos-config/cros_config_host/validate_config.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform2/+/a36f25bbddc6b8ad7372fffca6ead2342e343b9d

commit a36f25bbddc6b8ad7372fffca6ead2342e343b9d
Author: Simon Glass <sjg@chromium.org>
Date: Sat Dec 02 23:27:13 2017

chromeos-config: Support no-firmware on the firmware node

At present the 'no-firmware' tag is attached to the shared firmware node.
This means that it is not possible to control which models have firmware
at the finest granularity. Update the schema to work the other way around.

BUG= chromium:786519 
TEST=FEATURES=test sudo -E emerge --nodeps  chromeos-config-host
Signed-off-by: Simon Glass <sjg@chromium.org>

Change-Id: I303f5aca49d815c446d6c7a9b37b5d1543d8ada3
Reviewed-on: https://chromium-review.googlesource.com/804715
Commit-Ready: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Jason Clinton <jclinton@chromium.org>

[modify] https://crrev.com/a36f25bbddc6b8ad7372fffca6ead2342e343b9d/chromeos-config/libcros_config/test.dts
[modify] https://crrev.com/a36f25bbddc6b8ad7372fffca6ead2342e343b9d/chromeos-config/cros_config_host/validate_config_unittest.py
[modify] https://crrev.com/a36f25bbddc6b8ad7372fffca6ead2342e343b9d/chromeos-config/cros_config_host/libcros_config_host_unittest.py
[modify] https://crrev.com/a36f25bbddc6b8ad7372fffca6ead2342e343b9d/chromeos-config/cros_config_host/libcros_config_host.py
[modify] https://crrev.com/a36f25bbddc6b8ad7372fffca6ead2342e343b9d/chromeos-config/cros_config_host/validate_config.py

The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/platform2/+/ef841f2c1f06ce2402b23b91179d51001f9b0397

commit ef841f2c1f06ce2402b23b91179d51001f9b0397
Author: Simon Glass <sjg@chromium.org>
Date: Wed Dec 13 02:40:03 2017

chromeos-config: Support no-firmware on the host

We should not generate URIs for models which have no firmware. Update the
library to support this.

BUG= chromium:786519 
TEST=FEATURES=test sudo -E emerge --nodeps chromeos-config-tools \
        chromeos-config-host

Change-Id: I0d2e80b3bf8aeaca27da138976f91ad830beba1c
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/822157
Reviewed-by: Jason Clinton <jclinton@chromium.org>
Reviewed-by: C Shapiro <shapiroc@google.com>

[modify] https://crrev.com/ef841f2c1f06ce2402b23b91179d51001f9b0397/chromeos-config/cros_config_host/libcros_config_host_unittest.py
[modify] https://crrev.com/ef841f2c1f06ce2402b23b91179d51001f9b0397/chromeos-config/cros_config_host/libcros_config_host.py

The following revision refers to this bug:
  https://chrome-internal.googlesource.com/chromeos/overlays/overlay-reef-private/+/a6185ea9c59bb4a9c1053b7b13765a4d61740a2a

commit a6185ea9c59bb4a9c1053b7b13765a4d61740a2a
Author: Jason D. Clinton <jclinton@chromium.org>
Date: Fri Dec 15 21:23:45 2017