I have tried to upgrade the firmware of my K3.
I the first attempt it when well until installing of DSP1. Since then I have “ERR DSE” in the display.
I have used a USB to RS232 cable, and Windows 8.1 can find the cable without problems.
I have tried to move the cable to another USB plug and I have Changed the COM port No in Windows.
Present the radio has a dead RX and will not communicate with me at all.
73 Joe OZ0J