Plug a USB cable from your transmitter to your computer.
Before downloading the firmware, ensure your transmitter is compatible with the OpenTX 2.1 architecture. The following radios are fully supported: opentx 2.1.9 download
The desktop Companion software features better model conversion algorithms to prevent data corruption during transfers. Plug a USB cable from your transmitter to your computer
Pinch the two horizontal trim switches (T4 and T1) inward toward the power switch while turning the radio on. The screen should read "OpenTX Bootloader". select on the radio screen
Unplug the USB cable, select on the radio screen, and let it reboot. Method 2: Flashing from the SD Card