Apple is gradually abandoning the Lightning connector and switching to USB-C after The European Union forced it to do so. Many accessories, iPads, and even iPhones now use USB-C, the AirPods Max headphones are still stuck with Lightning. However, engineer Ken Pillonell (who implemented USB-C in the iPhone and AirPods before Apple) installed a USB-C connector on the headphones and is now selling a kit so that everyone can do the same.
Pillonel found that it was easy to knock out the Lightning connector and leave a hole that was the perfect size for USB-C. He then designed a special PCB and found the right connector to make it work. Pillonel managed to charge AirPods Max via USB-C on the first try.
Unfortunately, wired USB-C audio is not possible with this modification. Pillonel notes that this requires a chip from Apple’s own adapter, which costs $35, transmits Engadget.
The AirPods Max are three years old now, and they are likely due for an update. Any future model will likely have a USB-C connector to comply with EU regulations. However, if you want to work with your existing headphones (or maybe even replace a broken Lightning connector), you can download the circuit and buy all the other necessary parts. Everything is listed in the description of Pillonel’s YouTube video. In addition, you can buy set in the Pillonel store.