After shutting down the modem and before replacing the SIM, we generate
a temporary random IMEI to prevent accidental disclosure of the new IMSI
under the old IMEI. It should not happen but we do not control the modem
as much as we'd like, e.g. fully power it down. So it may not be
necessary but we consider it defense in depth.
When toggling the switch, a lock is held for a relatively long time,
preventing another toggling of the switch to be noticed. With this
change, I hope we can first shutdown the modem, wait for a toggle, and
then continue.
We're losing the abort function but I currently don't know how we would
be able to keep that functionality given that the toggle is queued and
we don't get the notification.