I have discovered a serious issue with Bluetooth connectivity on iOS 26.
My device use nrf52832 and sdk15.3, it consistently disconnects just a few seconds after a successful connection, then automatically reconnects in a continuous loop.
By using a Bluetooth packet sniffer and printing Bluetooth event logs, I found that iOS 26 sends a command to update connection parameters
" Control Opcode: LL_CONNECTION_UPDATE_IND" to Bluetooth slave devices (especially HID devices) every 120ms.
Moreover, the connection parameters it requests are also quite extreme.
The Bluetooth stack of the slave device cannot handle such a high frequency of update requests, ultimately leading to disconnection. Bluetooth stack shows a disconnection error code of 0x28, which corresponds to "Instant Passed."
I will attach my packet sniffer log images. I even suspect this is a very simple and stupid bug—the apple programmer mistakenly placed the Bluetooth parameter update procedure in the Bluetooth central callback event, causing a dead loop. The correct approach should be to request updates by a timer.
Our users are urging me to update the firmware to be compatible with iOS 26 every day. However, after trying some methods, I found that the problem could not be solved at all. Apple support also did not reply to my messages. Now I have no idea how to deal with this problem. Maybe someone in the community has encountered the same problem and solved it?
