When I plug in the Arduino MKR1000 with USB, run the latest Arduino IDE and upload a sketch it works fine. I installed the 1.6.2 driver.
When using MATLAB R2018a and use the Support Package for Arduino the MKR1000 also works fine.
But in Simulink when I use external mode and upload something the building works and the first time it’s writing the code on the board. But the second time the writing of the code to the MKR1000 won’t work. It says then that Simulink can’t automatically find the COM port. Setting the port manually to the one in the device manager for MKR1000 don’t work. Also unplugging and replugging don’t work.
After that error the device driver has changed from Arduino MKR1000 to Genuino MKR1000. I can’t reproduce a situation where I can make the board working two times in a row. Every time it’s coding the MKR1000 the second time won’t work. Also the setup from the Simulink Support Package works every time.