Earlier quoted context omitted.
Are the Huami ones open source or hackable?
Not really, no. Sort of. I have a Mi Band 5, and wanted to use GadgetBridge instead of the official Mi Fit or Amazfit/Zepp app. I was surprised to learn this was not easy to do. I needed to retrieve the Bluetooth MAC from the proprietary app via rooted app, or by logging in via script, which no layman would do. The watch is now paired with GadgetBridge, but the steps are hard enough to dissuade anyone from trying it.
> I have a Mi Band 5, and wanted to use GadgetBridge instead of the official Mi Fit or Amazfit/Zepp app.
> I was surprised to learn this was not easy to do. I needed to retrieve the Bluetooth MAC from the proprietary app via rooted app, or by logging in via script, which no layman would do.
> The watch is now paired with GadgetBridge, but the steps are hard enough to dissuade anyone from trying it.
There is now also an android app to fetch the key and gps almanac, very simple to do, no root or python required.
Note: I kivy wrapped and apk packaged the above mentioned script.