Q2686 locked in permanent reset cycle?


Currently: the LEDs on the SDK board flash off and on permanently with a 1 second period. HyperTerminal gets absolutely no response from the SDK board (HyperTerminal doesn’t even display any powerup WIND indicators). Battery or soft reset has no effect. If I enable the ‘boot’ switch on the SDK board, HyperTerminal displays üüü üüü üüü instead of the expected üüüüüüüüüüü. A can’t even get in to stop the application if that’s whats causing this funny response.

What I did: I loaded application firmware to the device. I’ve been doing this for the past few weeks now with no problems. No hardware touched today, so it’s not like a static discharge is to blame or anything.

Any advice? I’ve since swapped out the Q2686 for another one and am carrying on, but I’m very concerned that the other module is now useless.
Looking forward to any suggestions!


If you have DWLWin and the non-dwl firmware files you could try to bootflash the module.


I have exactly the same issue. I can still download new application firmware in it with DWLWin, or erase the application, but the modem keeps resetting.
It looks like the OS (6.61) is not working correctly anymore. I can only upload a new OS via the X-modem protocol and that’s impossible due to the continuous resetting.
Perhaps a watchdog reset has occurred during firmware install.
Did you already manage to find out the cause of the problem?
If not I will contact my distributor and they will ask the question to Wavecom.



I also have the same problem (I am using the Q2687).

Have you received any answers yet?



I did not receive a reply yet, but I have sent 3 modems with this issue to Wavecom for analysis.
I have downloaded OS 6.61 via DWLWin and erased my application and data, but the modem still resets.
I’ll post a message here when I have received an answer from Wavecom.


We have a similar problem. Our Q2686 resets after every one second. So, it’s impossible to load a new firmware, stop it, or sending any AT command.

Without making attention, I think we have loaded an OpenAT application V.4.11 when firmware is V.4.10.

So,after typing AT+wopen=1, i think this is why module is in a permanent reset.

So, Can anybody know how can i stopped this permanent reset ? anybody have already fixed this problem ?

Thanks in advance

Best regards.


You could try spamming AT+WOPEN=0 to the module while it starts/restarts.

Or reflash it with DWLWin if you have that possibility.


We have already tried AT+WOPEN=0, AT&F, AT+WDWL, while the module starts/restarts, but without any effects.

But, i don’t know DWLWin ? what is it ? where i can find it ? And how it works ?

Thanks for your help !


I received feedback on the three modems I sent to Wavecom:

We performed an analysis on this Wireless CPU and found that the problem is a known behaviour (cf CUS39756 and CUS40023).
The problem may occur when a A&D volume which is in a bad state has been formatted or assigned a new size.
Then an unexpected reset occurs while recompacting the A&D memory.
To prevent this, there should be a recompaction of the volume before any format or resize action.
The correction consists in sending an error message when the memory is in a wrong state and the user should then first recompact the memories.
This new error message will be +CME ERROR: 561 (Means : DOTA Volume State = AD_REPAIR; need Recompaction).
Unfortunately, correction for these anomalies are not in the scope of next 6.63 FW.
It will be integrated to the scope of the next FW on 6.6x branch.

If this is also the case with your modem, there is no way to get it working again, you have to take a new one




thanks for your feedback !

Single question : where can i find the description of this known problem :cf CUS39756 and CUS40023 ? in which datasheet please.


That’s what I’d like to know too, because I don’t have it also. I asked my distributor, be he also doesn’t have this information.

Kind regards,