Vogel's MARMITEK BoomBoom 55 HD Manual Del Usuario página 6

The pairing with the first Bluetooth device will be momentarily
interrupted, after which both Bluetooth devices will be paired
with the BoomBoom 55 HD. This can take up to two minutes.
Note: You can only change the codec when only one device is
connected.
Deleting paired devices from memory
To delete previously paired devices from the memory, proceed
as follows:
Turn off the BoomBoom 55 HD.
Press and hold the pairing button for 9 seconds.
Switch on the BoomBoom 55 HD.
Release the pairing button after 3 seconds.
All previously paired devices are now erased.