mLRS hardware using the SX126x/STM32WLE and SX127x LoRa chipsets are not compatible with each other and will not bind.
This is for two reasons:
- The 31 Hz mode uses spreading factor 5 (SF5), which is only available on the SX126x/STM32WLE chipset.
- The 19 Hz mode uses spreading factor 6 (SF6), which was modified on the SX126x/STM32WLE chipset making it incompatible with the SX127x chipset.
This is the relevant part in the datasheet of the SX126x chipset:
