To get the sensors working:

You need to create this file:
and here you'll find the needed content for the file: https://dpaste.de/BjZg

This has to go in your sparse folder, but you can test it on the phone first

The port number was wrong, I left it blank and it used 21. Now with 22 it works. Thanks.

Regarding the problem with the non storing wifi passwords...i had to build the wifi driver as a module and not directly into the kernel to get SFOS to store the passwords...do not ask me why

So, could be worth a try.

Do you know the driver name in the kernel config?

Now the screen rotation works.
How can I check what sensors do work and what do not?

Install messwerk from openrepos.net to check sensors.

You need CONFIG_MODULES=y and CONFIG_BCMDHD=m in your defconfig.

Thank you.
Excep the position and GNSS Satelites, everything else work now. (At least in messwerk the graphs shows the change.)

Now I am recompiling the kernel to fix the wifi problem.
However it would be good if I have a solution for the mobile data and the missing /android folder issues before I re-build the system again.

Plus, I am not sure whether I need to re-do the 13.2 and 13.3 steps again. And I still don't know how can I include an rpm into the build.

Low Power Mode (AKA "sneak peak" or "ambient display") also works.

Position and Satelites only work when GPS is enabled.

No, you do not need to repeat steps 13.2 and 13.3.

Found the solution for the missing android folder, you need this file:
https://github.com/mautz-kernel/droi.../android.mount

and a symlink to this file in /lib/systemd/system/local-fs.target.wants/

All this stuff also needs to go into the sparse folder.

Thank you!

This could also be usefull:

https://github.com/mautz-kernel/droi...-links.service

Symlink goes into multi-user.target.wants folder and you need the android-links.sh script from /usr/bin/droid too.