Quote from GeoAstra Official on February 3, 2026, 10:36 pm

To reset the RTU609BT, please send the following commands to the device:

freeset
gngga com1 1
gngga com2 1
gnrmc com1 1
gnrmc com2 1
gphdt com1 1
gphdt com2 1
gngsv com1 1
saveconfig

After running these commands, the RTU609BT will be restored to its factory default configuration.

Explaination:
freeset performs the factory reset.
After the reset, to re-enable data output, you must send the following commands again:

gngga com1 1
gngga com2 1
gnrmc com1 1
gnrmc com2 1
gphdt com1 1
gphdt com2 1
gngsv com1 1

COM1 maps to USB
COM2 maps to Bluetooth
saveconfig saves the configuration to persistent memory.