Here's updated instructions for installing the Betaflight Lua script to your OpenTX radio (Taranis X9D, QX7, Horus X10, X12). This video improves on my original one:
1. The Betaflight Lua script got easier to install, but the instructions changed so the original video doesn't work.
2. The original video didn't use the easiest way of updating the firmware.
3. The new Betaflight Lua script not working. It has an "out of memory" error when used with OpenTX 2.2.1. I'll show you how to fix that.
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My original Lua script installation playlist, with detailed instructions for installing Companion and updating your firmware.
However, I suggest you use the firmware flashing method shown in this video, not the one shown in that video. Still, that video will show you how to download Companion and set it up.