nrfutil dfu very slow compared to nrf connect dfu

[bds]

Using the same connectivity firmware, a dfu update using nrfutil takes about four times as long as the same update using nrf connect. I have to setup dfu updating in a production setup and need a command line driven dfu process. Any options to speed up nrfutil, or alternatives to nrfutil?

[Hung Bui]

Hi bds,

It's very unfortunate that the developer who worked on DFU on nrfutil moved. So I couldn't get hold of him. I had a look in the code and seems that it may requires some change in the lower level at pc_ble_driver_py library . You can have a look here at line 322. We send a write command and we wait for a TX_COMPLETE event before we continue. This explains why the nrfutil only send one packet per event.

It's possible to modify that and queue more packet and don't wait for TX_COMPLETE. Then retry when the buffer is full.

If you don't want to implement that, I would suggest to simply reduce the connection interval, for now it's 30 ms, you can change it to 7.5 ms and will have the update 4 times faster. To change connection interval you need to modify BLEGapConnParams in on_gap_evt_adv_report() in dfu_transport_ble.py. And update MIN_CONN_INTERVAL and MAX_CONN_INTERVAL in nrf_ble_dfu.c in the bootloader.

Another, better solution is simply use the node.js javascript that used in nRFConnect to do the updating. And you can do it on commandline. Have a look here, you can find the syntax

node dfu.js FF:11:22:33:AA:BF ./dfu/dfu_test_app_hrm_s132.zip

[bds]

No ideas?

I checked the serial port traffic with serial port monitor and it seems that on my computer, a serial port read action takes 1 - 2 ms. On another computer it always takes a fixed 15 ms. Could this be due to some Segger serial port driver configuration?