-ffancyqmi option increases the log level,
--poll activates polling instead of listening to unsolicited callback from libqmi-glib.
If client IDs are not released using
QmiNasClient::release() and the like, the error "
ClientIdsExhausted" can occur and even survive cold reboots.
As documented in the ac. mailinglist under the subject SYNC indiciations, performing an arbitrary
qmicli command with --device-open-sync can solve this:
qmicli -d /dev/cdc-wdm0 --wds-get-packet-service-status --device-open-sync