How to update firmware on Powerbeats Pro, if I have only one earphone and «Beats» require two to start updating? (Second one was lost years ago)

How to update firmware on Powerbeats Pro, if I have only one earphone? I lost the second one like... Years ago, then just forgot about these earphones, and now I want to use them. Without the update the only earphone left just shuts down after ten-twenty minutes (usually when reach 98%), because it wasnt updated for... Really long time. Its version is still at 5B66, and the last one is 6F8. I have Android, so they will not update automatically. But the «Beats» requires both earphones to be in the case to start updating! How can I uptade them to continue using?

(Sorry for mistakes, English is not my first language)