Hi,

On Thu, Feb 18, 2021 at 2:55 PM Douglas Anderson [off-list ref] wrote:

it's believed
that, under certain timing conditions, it could be getting the EC into
a confused state causing the EC driver to fail to probe.

Believed => confirmed

I _think_ <https://issuetracker.google.com/180655198> is public.  It
explains why this was causing the EC driver to fail to prove.  In
short: it turns out that when we glitched the EC it printed to its
console.  If the EC's uptime was long enough then it would spend
enough time printing the timestamp for this error message (a bunch of
64-bit divide by 10) that it wouldn't be ready for the message we sent
to it.  Doh!

-Doug