MintyBoost was a terrifically handy DIY USB charger, housed in an Altoids gum tin. It worked great, until Apple changed the way it charged devices, gimping third-party chargers. But have no fear! The MintyBoost team is on the case.
https://gizmodo.com/mintyboost-diy-aa-usb-charger-177527
What they found, and what’s enumerated in detail in the video below, is that Apple puts unusual resistor values on USB data and power lines. The result is a sort of DRM for hardware, that explains why third-party battery chargers don’t always work the way they should:
To read the full breakdown, head right over here to the MintyBoost site. And if you’d like to order your own kit, it’s available for $20 here. [MintyBoost, Thanks Philip!]