Follow these steps to upgrade the 1274B firmware:
- Use the RRC-Micro program to show the current 1274B firmware version and take a note of it. It can be found on the ‘About’ tab on the line looking like ‘Dongle 1274B x.x.x.x Firmware y’ where ‘y’ is the firmware version as a single number.
- Disconnect the USB cable from the PC.
- Press and hold the PTT button.
- Connect the USB cable to the PC(while pressing the PTT button). This should make Windows showing an USB Drive in an Explorer window with a single file called ‘firmware.bin” in.
- Release the PTT button.
- Delete the ‘firmware.bin’ file.
- Copy the new firmware file to the USB Drive.
- Close the Explorer window.
- Disconnect the USB cable.
- Connect the USB cable.
- Check that the new firmware was successfully flashed by repeating step 1.