Company engineers have been toiling away to address problems. One challenge is making sure the charger doesn’t overheat. Another is the complexity of the circuitry, according to people familiar with the device’s development.
Then there’s this:
The AirPower charger is also more advanced than the current competition because it includes a custom Apple chip running a stripped down version of the iOS mobile operating system to conduct on-device power management and pairing with devices. Apple engineers have also been working to squash bugs related to the on-board firmware, according to the people familiar. They asked not to be identified discussing a product that hasn’t been released yet.
Gurman says that Apple hopes to ship the charging mat by September, a full year after it was previewed.