That is strange, Leopoldo. When the transmitter and receiver are bound, they should stay bound. The binding process should cause the transmitter/receiver IDs to be written to flash memory inside both devices. There is no concept of partially bound. However, if one of the devices fails to write the device ID of the other to flash memory, then that information will not be preserved across a power cycling of the device.... Could you try the binding again and see if the same thing happens, please? If it does, you might want to open up a support ticket with Freefly: email to firstname.lastname@example.org. Andy.