Debugging HID/Keyboard with serial to another Puck?

As far as I understand it, HID works a bit like this:

• Device wakes, starts advertising
  
• PC/Mac sees it some time after
  
• PC/Mac connects
  
• It requests a list of services
  
• It does interesting things with those services and remembers stuff about them
  
• It requests to be notified to some of them
  
  

That all takes a bunch of time though, so even if you get the connected event I guess the HID might not have been initialised enough that a call to the NRF HID function would actually work.

What happens if you leave a reasonable delay (5 seconds?) between connecting and trying to send any HID packets?

Also, when you're getting that error, is your Mac actually showing the device as a HID device? Or does it show it as a normal serial device?

Are you calling setServices or setAdvertising more than once at all? I guess that could mess things up too - if the services change then the CCCD numbers might change, and that could confuse the computer.