(TECH) Xadow GSM+BLE module restarts with SIM


I have problem with my original (Kickstarter) module with inserted SIM card. Module is not running program, after powering on it restarts to USB mode. Without SIM module runs fine (i can upload sketch, have serial communication).

SIM is OK, no PIN, it works fine in newer module (bought later).

Is there anything to test? What can I try?

I tried to re-flash firmware (one from Arduino IDE) and module behaves in the same way even without any program loaded in.

Thank you for help.


I had the same problem. The battery must have 3.3 ~ 4.2V(no SIM)/3.5 ~ 4.2V(with SIM).
You can replace the battery

Thank you for suggestion with battery, but unfortunately this is not the case - it would not work on the 2nd module.


Hi Jan,Pacak,

Do you mean if you have the SIM card inserted, the Xadow GSM+BLE would fail to be turned on and cannot upload the sketches?

Could you please be more specific about the problems you are facing, it would help us solve it for you, thank you!

Yesterday evening I spent playing with it and re-flashed the Arduino firmware. Than i was able to start with sim and it was telling just without SIM. Today it is just ok. surpriseā€¦ :slight_smile:

The module behaved in the way i was not able to keep it turned on (with two serial ports). It immediately went to flash firmware mode.