DFU / OTA mode

[54696d21]

You commented on hackday.io that you tried to flash fitness trackers in DFU mode but that you didn't succeed. Could you explain what you tried so far? Do you have any knowledge on why it failed? Do you have any knowledge on whether the standard bootloader is installed on those devices? I paired my X9 with my phone and opened the NrfConnect App and saw that I could directly upload firmware from there. I'm going to investigate whether (and how) the DFU mechanism used in the official fitness tracker app differs from the one in the NrfConnect App.

To my situation: I just received X9 Pro and thought I could first of all give it a try to flash via DFU before I open it. My midterm goal is to get a water proof fitness tracker with custom firmware.
I know about Roger Clark's blog and I going to ask him as well.

By the way I saw a chinese fitness tracker company that "directly advertises" that it is possible to use the NrfConnect App for firmware updates: https://www.youtube.com/watch?v=d7r_g-YrPR8
and https://www.youtube.com/watch?v=I8BA3aHFKII

[curtpw]

This is interesting. I can see how this would be particularly significant for you given the waterproof requirement. I tried the standard bootloader as described for using the nRF52 DK but it didn't work for me. To be perfectly honest I haven't spent much time on this since my use case requires the addition of sensors and major enclosure modification. I'm going to take another look though. It may be that these devices vary widely in terms of bootloader customization.