MC8092: Win7, QMI mode, no conn. after Windows soft-restart

Dear polite fellow forum inhabitants,

I’m facing a funny quirk in a few pcs of the MC8092 in Windows 7.

The problem is:
If the machine first starts after a power-up, the 4G connection gets established in Windows using stored credentials and works fine.
If the machine is just soft-restarted from Windows (without the MC8092 losing electric power), on the next start-up the Windows “mobile broadband networking” connection manager cannot connect.

But, the modem is alive, I can talk to it using AT commands, and AT!RESET or AT!GRESET results in a restart of the modem (USB detach/reattach) and functional WWAN networking in Windows. The problem is that this machine needs to run unattended, so a failure to start a WWAN session after a soft-power-cycle is a problem. The modem also responds to a short to GND at pin 33 in the MiniPCI-e connector (WWAN SYSTEM_RESET#), if I short it to GND manually. The host PC (some Nexcom fanless box) does not pull this pin 33 low upon a restart - but reading the MC8092 “design guide”, I understand that a cold reset is far from mandatory, possibly quite the opposite is true, a HW reset should be avoided, a soft restart via the API or AT command are preferred…

Interestingly, in the “awry” state after a Windows soft-restart, the modem keeps throwing unsolicited !STKC messages. In the healthy state (after a cold power-up or an explicit modem reset) these are not present. Maybe the “SIM toolkit” is unhappy that the host Windows have restarted?

We’re using the MC8092 configured for QMI mode, with driver 16.8.1050.91.
The firmware in the MC8092 is tagged “SWI6600P_02.04.04.00AP R4125 CNSHZ-ED-XP0031 2015/07/14 23:01:24”
and apparently I’ve found that same image at Sierra Source… … ,00_00-fw/

Any ideas are welcome.
We buy the cards from Nexcom as an accessory to their PC’s, and yes I’m trying to get some help from them, but the progress is slow-paced.

Frank Rysanek


Please contact authorized distributor in SWI for your technical support to provide you the solution.
you can refer to below mentioned link to get the authorized distributor details.

Thanks and Regards,