Got a Clue but haven't got a clue

We've done it!! I used a mixture of values again, yours and the one from the Nordic dongle:

  'saved_code' : {
    'address' : ((223 - 10) * 4096),
    'page_size' : 4096,
    'pages' : 10,
    'flash_available' : 1024 - ((38 + 8 + 2 + 10)*4)
  },

Thanks for all that info, not that I really understand what we did or how it worked, mind you!