avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x00

Hello,

I try to use a shield designed by Embedded Artists using a ublox 2G/2.G chip. This shield is called sara-g350.

Here is my simple code:

void setup() {}
void loop() {}

When I upload it on my arduino uno alone, it works. However when i plug the shield and I try to upload the code, I get this message:

avrdude: stk500_getsync() attempt 4 of 10: not in sync: resp=0x00

It is said that this is due to a wrong choice of port or board. I've checked them and both are right. I think this is obviously due to a conflict between the arduino uno board and the shield, it may be on the serial port. There is no jumper or switch on the shield. Nothing about it in the documentation.

Someone could help me out with it ?

Thanks /Chris

There can be a problem with impedance load on pins 0,1 - rx,tx. They cannot be used by both devices, onboard USB/serial transceiver and shield. Shield must be disconnected before each upload.