iPhone issues with HFP SSP pairing (ESP32)

[danjulio]

I am using the Bluetooth classic HFP (latest v4.4.4 IDF) in an application. I have enabled SSP in the configuration and have support in the code for it. It seems to work fine. However I have seen an issue when pairing with iPhones (both iOS 15 and iOS 16). Instead of displaying the 6-digit code, the iPhone displays a dialog asking if I want to allow the device access to the address book and the pairing fails because it never displays a 6-digit code (see picture below).

I'm not sure where the problem is. It could be an iOS issue. However since the ESP32 Bluedroid stack doesn't support the PBAP (phone book) profile, I'm not sure why the iPhone is displaying this message at all.

Has anyone else seen this and have a work-around or fix? Someone else must have created a HFP app that uses SSP.

Is this an issue with the ESP32 Bluedroid stack advertising a capability it doesn't support or iOS simply assuming any HFP device will have PBAP functionality?

Thanks, Dan

iphone_addr_book_req.png (588.44 KiB) Viewed 1412 times

[MicroController]

It seems to work fine

Works fine with...? Other phones (Android)?

iOS simply assuming any HFP device will have PBAP functionality?

Most definitely.
AFAIK, the hands-free (HF) unit sends AT commands to the AG (phone) to e.g. accept or initiate calls. Other AT commands over the same channel are used to access the phone book, so it's not about bluetooth or advertising but actually about if the phone will accept certain AT commands from the HF should the HF try and send those. Whether or not the HF can/will use any phone book commands later is unknown to the AG.