SD-35, SB-55: 'bFL' (Buffer Full) Message
In order to record any MIDI information quickly, and/or in massive quantity,
you should turn Soft Thru off. This prevents the SB-55 or SD-35 from trying to
pass the incoming data 'thru' to the MIDI Out port which requires the processor
overload in some cases - depending on the speed and quantity of the data.
1) While holding the SET button, press the left SONG button.
2) Use the REW and FF buttons to change the display to 'oFF.'
3) Press the SET button to finish the operation.