Hey thanks for the answer. I'm working with MKRNB1500. I'm uploading the firmware with the steps covered in the Firmware upgrade for UBLOX SARA-R410M-02B on the MKR NB 1500 #2 which include soldering USB cable on the board. It is firmware version [SARA-R410M-02B-03-L0.0.00.00.05.12_A2.19_IP.zip]. Basic sketches work but anything with the SARA-R4 seems to cause the bootloader to go off after a couple seconds.