I followed this guide to turn my pi into a HID keyboard. The basic idea is you use code to send whatever keystrokes you desire. It seems to be working with macOS but not iOS. I am using a lightning to USB adapter. The phone powers the pi but does not recognize it as a keyboard. I know the iPhone can only provide a certain amount of power to USB devices so I set this value to 100mA. Any other ideas why it isn’t working? Thanks.