Thank you for your support, I managed to make a Firmware Update with UE + instructions you provided(115200 baud + manual reset). We have also connected successfully to our Server via sim card connection using AT commands. However, we still have a problem, it may not relate to the board. After plugging MKR1000 to the computer to use AT commads it does not reply. We pull out the Tx Rx pins, waiting about 5-10 seconds, than plug in those pins and then we get reply and all working fine. Could it be compatibility issues or MCU related problem?
We use 9600 baud rate during AT commands, We use Serial1 for rx/tx pins, We have a code like
and then just use
Thanks for all your help, we could make a huge step forward!