title: How can I make Raspberry Pi's Bluetooth discoverable to iPhone?
body: <p>I've got a Raspberry Pi 4B,
  when I use an Android phone to connect to the Pi with Bluetooth, it works normally, both pairing and connection.
  But when I use an iPhone to do the same thing, the phone can not see Pi's Bluetooth, it means, the Pi's Bluetooth is not discoverable to iPhone.
  (However, the iPhone's Bluetooth is dicoverable to  raspberry, but this is not what I need.)</p>
  <p>Could anyone tell me, is there anything special of iPhone's Bluetooth?
  What should I do if I want to make Pi's Bluetooth discoverable to iPhone?
  I want to connect to Pi's Bluetooth from iPhone.</p>
  <p>Update according to ukBaz's advice,
  I am not sure what to do with Bluetooth next, but first I want to let iPhone pair with the Pi, now iPhone simply can not find the Pi's Bluetooth.</p>
  <p>The way I make Pi to be discoverable is to run a shell script when Pi starts, through correcting the file /etc/rc.local.
  the content of shell script is something like below,</p>
  <pre><code>sudo bluetoothctl &lt;&lt; EOF  
  discoverable on
  pairable on
  exit
  </code></pre>