RE: Cannot re-bond when peer is deleted from nRF52 but not from iOS

Einar Thorsrud — Tue, 06 Apr 2021 12:32:43 GMT

Hi,

[quote user=""]Is there a way to allow the SDK to repair without removing the bond from the phone?[/quote]

In the case you describe, the bonding information is removed on the nRF but not on the iPhone. There is no to pair these devices again without removing the bond on the iPhone as well in this case. This is for security reasons, and unlike the nRF SoftDevice, the BLE API on the iOS does not allow you to specify that bonds can be overwritten (or even delete bonds from an app, as you write). So in other words, there is nothing you can do with this issue from the nRF side if you use bonding.

[quote user=""]Our alternative is to maintain a larger peer list (rather than delete the previous peer with each new bond) and only add our single desired device to the whitelist, but we'll still need to limit the peer count and we may eventually encounter the limit and need to delete a peer. Meanwhile, the phone's bond may still be present.[/quote]

This approach is viable. I do not see any problem with this. As you write, you may need to delete bonds at some point (though if you have a lot of flash space available that may be more theoretical then practical depending on how your product is used). If so, you would be back to a situation where the bond would have to be deleted on the phone for any deleted bonds. Note that the peer manager library has a concept of peer ranking, so you can easily find out which bonds are recently used or not, and only delete bonds that have not been recently used.