BLE DFU Speed difference between SDK14.2 and SDK15.3

[SciTER Development Team]

Config1:
MCU : nRF52840
SDK : SDK15.3
Softdevice : s340_nrf52_6.1.1_softdevice (SDK15.3)
Phone: iOS version 12.1

Config2:
MCU : nRF52832
SDK : SDK14.2
Softdevice : s332_nrf52_5.0.0_softdevice (SDK14.2)
Phone: iOS version 12.1

We have use SDK Bootloader example code for both SDK14.2 and SDK15.3 for BLE DFU. Our bootloader is based on the BLE secure bootloader example from SDK14.2 and SDK15.3

Now if we use SDK14.2 then it will take max 2 minute for BLE application upgrade.
and if we use SDK15.3 then it will take around 12 to 15 minute for BLE application upgrade.

Note: Application file size which is used in both upgrade is same.

so my question is for SDK15.3 boothloader example code takes more time then SDK14.2 bootloader example code.
Why it takes more time?

I use same app and mobile device in both condition.

Thanks,
Sandip Divani

[Himansu]

Hi,

Query: How to Enable Data Length Extension using Application nRF Util?

- Peripheral Device:
nRF52840 Chip-set

- Central Device:
nRF52840 DevKit

- Central Device controlled using Application nRF Util which is useing for testing:
github.com/.../pc-nrfutil

- Used Command:
nrfutil dfu ble -ic NRF52 -pkg E:\App.zip -p COM6 -n "DFU" -f -mtu 247

Regards,

Himansu

[Hung Bui]

Hi Himasu, 

If you are using nrfutil, please make sure you used the latest version and the softdevice you used for the firmware is >3 . You can find the code where longer data length is requested here: https://github.com/NordicSemiconductor/pc-nrfutil/blob/master/nordicsemi/dfu/dfu_transport_ble.py#L170

On the bootloader side we don't set a certain data length but simply follow what's requested and max supported. Check BLE_GAP_EVT_DATA_LENGTH_UPDATE_REQUEST event inside ble_evt_handler() in nrf_dfu_ble.c