How can I use a BlueSMIRF Silver (RN-42) as a HID Keyboard (on IOS)? I've got a BlueSMIRF Silver (RN-42) Bluetooth module.
I am trying to create a basic keyboard I can play with on an iPad Air.

At the moment barely manage to get the module to pair with OSX
but only through using Bluetooth Setup Assistant and using "Passcode Options...use a specific code". 

With this option, the module pairs, but the connection resets about every 5 seconds. 

On iPad it tries to use a generate number really fast and fails straight away, being unable to connect.

I noticed there is a BlueSMIRF HID version, but from what I can tell, the hardware is the same, 
just the firmware is different. I've gone through the whole Bluetooth Data Module Command Reference &amp; Advanced Information User’s Guide(pdf link) manual and from what I can gather,
even though I have Silver firmware burned onto my module, I should be able to set and use the HID profile
(from the default SPP):


  Roving Networks modules shipped with firmware version 6.11 and higher
  support the HID profile. You do not need special firmware if your
  module is running firmware 6.11 or higher.


and my module reports version as:

Ver 6.15 04/26/2013
(c) Roving Networks


I've also gone through the Bluetooth HID Profile(pdf link) guide from Roving Networks, but the same information is present in Chapter 5 of the advanced user's guide mentioned above.

I've setup the following settings (with commands used):


HID Profile (S~,6) 
Device discovery and pairing is set to automatic, without using GPIO6(SM,6) 
HID Flag is set to Keyboard (SH,0000) 
Authentication is set to open (SA,0)


I've also tried the inquiry scan(SI,0800)  and page scan(SJ,0800)  windows to maximum 
in the hope it would increase the odds of successful pairing and made sure I rebooted the module and checked the settings again.

I have used the same module with the SPP profile just fine, but I'm still fairly new to Bluetooth
and this is the first time I try to use the HID profile.

How can I use the BlueSMIRF Silver as a basic Bluetooth Keyboard for an iPad Air ?
I should be able to set and use the HID profile (from the default SPP)


Unfortunately, your assumption is incorrect. From the same documentation you quoted, the previous sentence says:


  To use Roving Networks’ Bluetooth HID profile, you must use a special
  build of firmware, version 6.03 or later.


Poorly phrased, this does mean that you need to have two things:


A special HID firmware 
Version 6.03 or later


Your BlueSmirf Silver only complies with the second condition; it does not have the special HID firmware (also note that the Rovnix command reference does not address a specific variant of the BlueSmirf, but speaks generally about all of the variants).

The SPP protocol (Serial Port Profile) is used for emulating a serial cable, and functions as a substitute for the physical RS-232 connection, but cannot stack pure HID profile on top of it. In order for you do talk HID, you will need the HID firmware. 

As a side note, the HID version comes with SPP and you can switch between the two modes interchangeably, I have been using the HID version for a while now and it works fine (including the pairing with iOS). 

Another misfortune is that it does not appear that Roving Networks officially support any re-flashing of the BlueSmirf firmware, so unless you are willing to reverse the hardware, this is off the table as well.