I've just released a bug fix for 2.78, which is called 2.78b. This fixes a bug in the new RSSI_RANGE option spotted by forum member Valince.
The bug was that RSSI_RANGE used the same parameter key in EEPROM as the RC1 parameter set. That is an important bug, as setting RSSI_RANGE would cause the RC1_MIN parameter to be reset to its default value of 1100 on the next boot. Additionally, setting RC1_MIN would cause RSSI_RANGE to reset to its default value of 5.0.
Many thanks to Valince for spotting this bug!
I've now pushed a change to our parameter handling code to automatically check for this type of error on every boot, so it can't happen again in the future.