FALLBACK
On the Linn DS/DSM the FALLBACK button is used as part of the recovery procedure.
This FALLBACK button should ONLY be pressed briefly when the Linn DS/DSM is powered on. This action will start-up the Linn DS/DSM into Software Upload mode with a lightening flash on the front panel display. That is, it is waiting for the Konfig software to transfer the software into it.
To bring the Linn DS/DSM out of the "Software Upload" mode, with lightening flash, all you need to do is power cycle the Linn DS/DSM. That is, switch mains OFF for 10seconds and switch Mains back on.