Why does Nordic_Uart sample do an illegal response for iPhone X?

[Yoshihiro Goto]

I am trying to communicate with iPhone X using Nordic_Uart sample project in SDK 14.2. And I check the Protocols between nRF52DK and iPhone X by using Ellisys Bluetooth Tracker, I found an error on LLCP Length Response. LL_LENGTH_RSP.png

The nRF52DK responses a value of 313 as both MaxTx and MaxRx for iPhone X. why does this incomprehensible thing occur?

[ovrebekk]

Hi

You are not the first one to report this, so this is something we have to look into. Currently most of the R&D guys are out in Christmas holidays, but we can look into it next week.

Are you able to share the log file from Ellisys? Then it's easier for us to look into it (we don't currently have the iPhone X in the office).

Best regards

[run_ar]

@Yoshihiro Goto: could you try these things: 1. set a defined length when calling sd_ble_gap_data_length_update instead of NULL for dl_params. 2. setting PHY to 1mbit when calling sd_ble_gap_phy_update instead of setting it to Auto.

[Yoshihiro Goto]

here is an attachment of log with Ellisys. iPhoneX.zip

[Chris]

any news on this? we're not able to connect to any nRF52 device with iPhone Xs

[run_ar]

This seems like a but in the softdevice, but I have still been able to connect. Looks like iOS will continue with it's maximum length. Anyway the workaround seems to be not to use Auto when setting the Length when replying to the Data Lengt update request after the PHY is updated to 2mbit.

Note that if you do not handle the PHY request event in your firmware, iPhone x will not do service discovery. If that is the case please consider creating a new question for you issue. Preferably including sniffer logs.