nrfutil DFU upload extremely slow

[Florian Zierer]

as already written in other threads (two years old) the DFU upload with nrfutil is extremely slow.

Transferring the same data from a smartphone (with BLE5) takes about 20seconds, with nrfutil 2 minutes or more.

We use nrf52840 DKs for the PC side and our board.

We use the following command to run the update.

nrfutil dfu ble -ic NRF52 -pkg app_dfu_package.zip -snr $(NRF52840_SNR_BLE) -n "MY_NAME" -f -cd 0

nrfutil version 6.0.0a1

What could be the reason for the slow update. Is there anything we can do to speed this up?

[Edvin]

Hello Florian,

I took a sniffer trace today. You are correct. I compared the sniffer traces of nrfutil 6.0.0 and nRF Connect. Using nRF Connect the master (the DK that is used by nRF Connect) requests an MTU size of 247Bytes. Nrfutil also does this, but right after this request/response, nRF Connect requests LL_LENGTH_REQ (Data length extension) of 251 octets. Nrfutil doesn't do this.

I have reported this internally. I believe this issue is not present in nrfutilv5.0.0. 

FYI our nrfutil team has updated the softdevice used in nrfutil 6.0.0, which is probably why this was left out by a mistake.

Best regards,

Edvin

[Florian Zierer]

Hi Edvin,

great that you can reproduce the issue.

If I can help to test a fix, please tell me.

The problem is, that when using pc-ble-driver-py with python 3, nrfutil 6 is a dependency so its not so easy to install an older version.

[Edvin]

I understand. I have reported this to our team that write our tools. Hopefully, they will be able to patch it soon.

BR,

Edvin

[Florian Zierer]

Hi Edvin,

I just tested with nrfutil 6.0.1 and it is much better now.

Thanks for fixing it.

Florian

[Edvin]

Hello Florian,

Glad to hear that it was fixed. Again, thank you for reporting this bug.

Best regards,

Edvin