SC field in AuthReq pairing response

[Lorens]

Hi, I noticed that I can't bond successfully with my device using iOs 9.1 with Nrf Master control panel iOs app. When I insert the PINCODE, the device immediatly disconnects, and debugging it seems that iOs sends a diconnection command (BLE_GAP_EVT_DISCONNECTED). I read that this problem is due to the fact that iOS 9 is now using the new LE Secure Connections pairing model, and the SC bit is set to 1 in the pairing request. (stackoverflow.com/.../ios-9-1-ble-connects-and-immediately-disconnects)

I checked in the bluetooth core V 4.2 specs that in bonding procedure there is that bitfield in the octect 3 of pairing response called AuthReq, but I couldn't find any way to set it with softdevice 8.0.0.0. I guess the problem could be that one, but I couldn't find a way to test it. So is it possible to change that bit or do you have any information about that problem? I know S110 8.0.0.0 is compliant to V4.1 bluetooth specs, but I have this problem and I don't know how to fix it.

Thank you

[Ulrich Myhre]

@RK: I don't have the HW to test this at the moment, but looking at the 8.0.0 code, the whole preq is copied verbatim from the radio. And in the pairing confirm generation, it is again used without modification. There are also conformance tests to verify that we correctly ignore these fields, so I believe this is not the problem. But the tests and the current stack have changed a lot since 8.0.0, so my memory can be fuzzy.

@Lorens: The disconnection reason was not provided still, and this could quickly solve this. If it's "MIC Failure", then something is up with the key generation. But if it's just "Remote peer disconnected", then it's likely that iOS just killed the connection because nothing interesting was happening. I think they operate with a few seconds of timeout before they tear it down. Are you also able to pair without mitm?