1. Remove "nRST->LOW" and "nRST->HIGH" ,at the same, dont connect the nRst.
2. Add "delay(20us)" after "CS(using GPIO)->LOW" and add "delay(20us)" befor "CS(using GPIO)->HIGH
   "
3. Retry it, Pls.

@k2ironman So you need to write your own code to do that。 (Process serial port data according to protocol)

@privvyledge Refer to the link part 9(330)https://forum.aceinna.com/topic/93/top-topics-of-common-operations-with-openimu-products/2
If you haven't changed the calibration data, you can ignore it.Just burn the firmware.

@k2ironman look the part 4.2
OpenRTK330LI EVK用户手册_Release_Dec2020_CEK.docx

@privvyledge Please burn the firmware through STlink and I will provide you with a firmware file.OpenRTK330L_GNSS_RTK_INS_v23.01.bin