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,

So the device that is "connected" to nrfutil, the nRF52840 DK. Can you please test by using the same DK on nRF Connect for Desktop to perform the DFU? Is the speed the same there?

What nRF chip does your target use? I assume that this is not the issue, since it is faster using the smartphone.

The nRF52840 DK is erased at one point between two years ago and now? So that it is not running the nrfutil FW flashed 2 years ago? Try "nrfjprog -e" before the "nrfutil dfu ble ..."

So. 

1. Please test nRF Connect for Desktop.

2. Please try to update nrfutil to the non-alpha version 6.0.0 found here. 

Let me know about your results. 

BR,
Edvin

[Florian Zierer]

Hi Edvin,

the connectivity firmware on the nrf52840 DK was recently flashed.When using nrfConnect (2.6.2) another fw is flashed.

With nrfConnect the upload speed is similar as from a smartphone.

The target uses also nrf52840.

The non alpha version shows the same behaviour.

We tested this from Linux and Windows.

Florian

[Edvin]

Hello,

Do you have an application hex that I can try that is about the same size as the one you use?

What is the throughput (approximately) when you use nRF Connect for Desktop?

When you measure the time using nrfutil, do you time it from you see the progress bar, or from you start programming the connectivity board (the pca10056)?

[Florian Zierer]

Hi Edvin,

unfortunately, I can't share the hexfile.

nrfConnect shows 8-9 kb/s.

With nrfutil, I stop only the time when the progress bar is visible. Usually, the connectivity fw is already flashed so I start it without -f.

Could it be the missing 2MBit mode in nrfutil? At least in pc-ble-driver-py it is not directly available. (https://devzone.nordicsemi.com/f/nordic-q-a/54895/phy-update-procedure)

[Edvin]

I don't think 2MBPs is supported in nrfutil, no, but it isn't in nRF Connect for Desktop either. 

Can you please double check what version of nrfutil you have in your path? You can use the command "nrfutil version" from a folder that isn't in the same folder as nrfutil.exe, to make sure that you have the correct version in your path.

nrfutil and nRF Connect use a very similar FW. What was updated in a recent version (not sure which one) was that they started to use longer MTU and DLE, which significantly increases the speed.

BR,
Edvin

[Florian Zierer]

Hi Edvin,

I'm definately using nrfutil 6.0.0.

Is DLE used in nrfutil? I can't find any reference in the pc-nrfutil repository to e.g. BLEGapDataLengthParams from pc-ble-driver-py.

Or is this a default setting to use DLE?

Florian

[Edvin]

Can you please confirm what it prints when you write  "nrfutil version". I don't mean to be rude, but I just want to know that we are looking at the same tools when we try to figure out the cause of the speed difference.

I don't know the details about nrfutil and what it uses or not. I have to dig into some documentation or source code, but I want to know what version to dig into first.

BR,

Edvin

[Florian Zierer]

Hi Edvin,

It is nrfutil 6.0.0 installed from pip.

$ nrfutil -v -v -v  version
nrfutil version 6.0.0
2019-12-12 06:58:39,406 PyPi URL: pypi.python.org/.../nrfutil
2019-12-12 06:58:39,406 GitHub URL: https://github.com/NordicSemiconductor/pc-nrfutil

I just had a look at the sourcecode, and I could run nrfutil also from the github repository, so if there would be some improvements, I can test them.

Florian

[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