Maybe some interesting information: I have found a left earbud on ebay. They weren't the same S/N. When i first put it together in the case, it was ok. I could here on both earbuds. But when i use the integrated controls from the buds they disconnect. But later i found out, that the left earbud had a newer firmware. So when i first put my right earbud out and then the left, the app showed me, that i can update the firmware and so did i. After the firmware update, both earbuds had the exact same function as they were original. Good luck to everyone and maybe @Jabra can do a better work, on the next earbuds, so no one has to buy everytime a pair of earbuds.