Bang & Olufsen Beoplay Portal PC PS Mode D'emploi page 16

FAC TO R Y R E S E T
To restore your headphones to the factory settings,
do a very long press (more than 8 seconds) on the
button on the left earcup, until the LED indicator
flashed red. Then wait for the headphones to turn off
before starting the set-up process again.
Note, this will remove all paired devicess including
the Dongle).
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