Connect the power adapter to the wall while holding the reset button, right after inserting the USB cable. Alternatively, redownload the firmware file to rule out corruption.
Alright, putting it all together with these points in mind. Use a friendly but authoritative tone. Make sure to disclaim any uncertainties about the firmware's availability as free software unless I'm certain. Since I'm not aware of a specific project for Sun50iw9p1, I'll phrase it in a way that suggests community support and possible open-source alternatives without overstating.