You can always open the Bang & Olufsen app again and follow the steps to resume the software update from where you have stopped.
How do I update my Beocom Portal with the latest software?
Note: Please do not close the app while updating your headphones and remember to have your mobile device and headphones close to each other. The light indicator will pulse green while the update is in progress.
When the update is done, it will take approximately 30 seconds for the headphones to reboot. When the light indicator turns solid white, your Beocom Portal have been updated and are ready for use.
If connected to Beocom Link A or Beocom Link C, the light indicator will turn solid blue (Beocom Portal UC) or solid purple (Beocom Portal MS).