Connection issues with Android 6.0 Marshmallow and Nexus 6

[Mario Amigot]

Since Google released Android Marshmallow 6.0 we are experiencing problems when connecting our nRF51822 based peripherals to a Nexus 6 phone. The Nexus 6 is able to see our peripherals' advertisements while scanning but when it initiates a connection to a peripheral by sending a CONNECT_REQ packet, in that specific nRF51822 the BLE_GAP_EVT_CONNECTED event is never thrown by the S110 softdevice stack so the connection is never established. The thing is that the same application run in a Nexus 5 with Android 6.0 works without any problem.

Has anybody experienced similar issues with Android 6.0 and Nexus 6? Any idea what may be going on or a solution to this?

[Tru Pheenix]

I can confirm this. I am using the Red Bear Lab BLE Nano board with the S110 softdevice.

Our peripheral is configured to advertise as an iBeacon and is also connectable as a UART device.

On Android Lollipop and below, the Nexus 5 works fine. On Marshmallow, the Nexus 5 connects the first time. But if we turn off Bluetooth and turn it back on again the Nexus 5 refuses to connect.

On the peripheral, there is no connection request received.

Will anyone tell me what this issue is about? I'm using MBED to develop my firmware.