Double-check that TX and RX pins are reversed properly. Power cycle the box immediately after hitting start. Bad data transmission line or incorrect Baud rate setting.
While there isn't a single famous academic "paper" titled after the Sunplus loader tool, it is frequently discussed in technical reports and security research regarding firmware vulnerabilities in computer peripherals Key Technical Discussions & Research Firmware Security Vulnerabilities sunplus loader tool
However, for modern dash cams and hi-res players, manufacturers have moved to (copying a .bin file to an SD card), making the Loader Tool obsolete for those specific devices. Double-check that TX and RX pins are reversed properly
Note: Use modified versions at your own risk. They can physically wear out NAND cells if misused. While there isn't a single famous academic "paper"
Click "Start" on the loader and then power on the receiver. The tool will begin syncing and transferring the data.
Whether your PC has a or if you are using a USB adapter