You downloaded the wrong radio variant. Double-check the filename. An X9D bin file will not work on an X9D+.
This version supported high-quality voice readings. Users could assign voice alerts to critical events—such as "Low Battery" or "Landing Gear Up"—triggered by logical switches. It was one of the first versions to handle the .wav file structures efficiently on the SD card. opentx 2.1.9 download
Download exclusively from the official OpenTX GitHub repository. Pair the firmware with Companion 2.1.9. Back up your models. And if your radio hardware supports it, consider testing the waters of OpenTX 2.3 for expanded module compatibility. You downloaded the wrong radio variant