The last working image is 25.5.0-trunk.256, which is still available for download. I will try to look into the situation as my time allows. Thanks for the hint where to start.

I am always happy to see people keeping old hardware running. But I think it would be best to make the necessary changes in Armbian itself. I am happy to help out where I can be useful.

The ones I linked. You mentioned that you have no experience to compile stuff. One option is to target another SBC or a virtual machine so that you can focus on learning the build framework (explicit instructions are already given in some of the links) instead of having to deal with a multitude of issues (setting up your compilation host, getting compilation to succeed, finding the artifact to flash, only to then run into the next issue that armbian currently does not support your board). With a virtual system, you can be sure that you should get a working image. You can then focus on the compilation and familiarize yourself with that before jumping into real hardware enablement.

Do you have specific instructions for installing the X96 X6? @Chris4arm Thank you very much.

I added a suggestion at the PR how to implement the driver while building to allow network oob.