[Gta04-owner] [Community] About cost and business models for community hardware

Neil Jerram neil at ossau.homelinux.net
Tue Sep 29 20:45:52 CEST 2015

On 25/09/15 19:52, Lukas Maerdian wrote:
> Am 25.09.2015 um 20:30 schrieb H. Nikolaus Schaller:
>>>> * stable modem is IMHO already shown with Replicant (there are some tricks to stabilize the modem)
>>>> That's interesting.  Can you give or point to more details?
>>>> Specifically, is there now an effective recipe for:
>>>> - detecting when the modem has gone into a bad state
>>>> - restarting it?
>> Lukas can comment better on this.
> I did not run any longtime tests (or special tests for modem stability),
> but in my normal tests I could not observe this problem.
> Neither did I get any reports about this problem from other users.
> I remember the problem had something todo/could be influcenced by the
> AT_OPSYS command, which can be switched from the Android Settings GUI
> [1], if somebody wants to run some tests.

Yes.  I believe AT_OPSYS=3,2 allows the modem to use 3G, whereas 
AT_OPSYS=0,2 tells it to use 2G only.

With AT_OPSYS=3,2, last time I tried, a modem reset could be observed 
within about 5 minutes by enabling and using 3G data while in a moving 

> Another quirk which was introduced to better support our modem is a
> workaround for the broken AT+VTS command in the firmware.

Pointer, for posterity?

> Best,
>    Lukas


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