nrf54l15 android 7.0 nrf connect 4.26.1 cannot connect stably

[Nordfield]

MCU:NRF54L15，NCS SDK V3.2.4，android 7.0, nrf connect 4.26.1, cannot connect stably.

about 40 seconeds, the connect will disconnect, the android 7.0 side:reason is 0x08, the nrf54l15 side, reason is 0x22
prj.conf 

CONFIG_BT_AUTO_PHY_UPDATE=n

CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS=n

[Amanda Hsieh]

Hi,

MCU:NRF54L15，NCS SDK V3.2.4，android 7.0, nrf connect 4.26.1, cannot connect stably.

Does it only happen to Android 7.0? Could you try another newer Android version?

Could you provide the nRF-Sniffer-for-Bluetooth-LE log?

prj.conf 

CONFIG_BT_AUTO_PHY_UPDATE=n

CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS=n

Does it work if you remove these two configs? 

Might I know any special reason to disable automatic PHY updates and connection parameter updates? 

Are you able to reproduce the issue on nRF54L15DK? Or does it only happen on your custom board?

Regards,
Amanda H.

[Nordfield]

On my board,no nRF-Sniffer-for-Bluetooth-LE log, android 14, nrf connect 4.49, work ok.

[Amanda Hsieh]

Nordfield said:

android 14, nrf connect 4.49, work ok.

Seems the issue is on Android 7.0, which might have a restricted connection parameter requirement. 

Does it work if you remove "CONFIG_BT_AUTO_PHY_UPDATE=n" and "CONFIG_BT_GAP_AUTO_UPDATE_CONN_PARAMS=n"?

[Nordfield]

Maybe that, The Copilot can not fit it too.

[Nordfield]

But, the nrf53832，sdk 17.0， android 7.0 , work ok.

[Amanda Hsieh]

Nordfield said:

the nrf53832，sdk 17.0， android 7.0 , work ok.

You can refer to the connection parameters from that project or compare their sniffer logs to find the differences.  

[Nordfield]

But the protocol stack is different, and the implementation details may vary in ZEPHYR. Fortunately, there are few old Android devices now, so we can temporarily ignore this issue. Compatibility is indeed quite troublesome, so for now, the focus is on WIN11 and new mobile devices.Thank you!