Assistance Needed for Runtime change LE 1M PHY to LE 2M PHY on nRF5340 for Faster DFU Process

[Kaushik Parsana]

Dear Nordic Team,

We are currently developing a smart door lock using the nRF5340 and have started with the Matter lock sample demo code on our custom hardware.

To optimize the DFU process over SMP, we aim to switch from LE 1M PHY to LE 2M PHY at runtime. To achieve this, we have enabled the following configurations in our lock(BLE Peripheral) prj.conf file:

CONFIG_BT_PHY_UPDATE=y
CONFIG_BT_AUTO_PHY_UPDATE=n
CONFIG_BT_USER_PHY_UPDATE=y

However, when attempting to change the PHY from LE 1M to LE 2M using the nRF Connect app on an Android device, the PHY does not switch as expected.

Could you please advise if there are additional configurations or steps we need to implement to enable this functionality?

Thank you for your assistance.

Best regards,
Kaushik Parsana

[Hung Bui]

Hi Kaushik, 

Since the NRF53 has the controller running on network core. You may want to put the configuration CONFIG_BT_PHY_UPDATE=y to hci_rpmsg.conf file inside child_image. 

If it doesn't help, please try capture a sniffer trace so we can check why PHY is not updated. You can start testing with simple application instead of the Matter lock demo. 

[Kaushik Parsana]

Hi Hung,

I have enabled `CONFIG_BT_PHY_UPDATE=y` in the `prj.conf` file of the Multiprotocol_rpmsg child image folder, which is used for the network core in our project. However, I am still unable to set the preferred PHY level.

Thanks,

Kaushik Parsana

[Hung Bui]

Hi, 
Please try to capture a sniffer trace. 
Please also try to request PHY change from the peripheral side. 

[Kaushik Parsana]

snifferLogs.pcapng

Hi Hung,

Please find the attached file containing the sniffing logs. I applied the filter btcommon.eir_ad.entry.device_name contains "HU:D114" during log capture, as "HU:D114" is my BLE advertisement ID.

Kindly review the logs and advise on the next steps.

I have debugged a few things and found the following settings in the `build/zephyr/.config` file:

- `CONFIG_BT_USER_PHY_UPDATE=y`
- `# CONFIG_BT_AUTO_PHY_UPDATE is not set`
- `CONFIG_BT_PHY_UPDATE=y`

Additionally, the `CONFIG_BT_PHY_UPDATE=y` setting is enabled in both the child image and the application image. Which means configuration was proper.