in that you do exactly what people say to do, and it goes wrong.
The first tip is to repo sync repo sync repo sync. I say this because many of my own build problems were caused by not actually having the whole source code.
However most people's problems, say the camera not working, or the build not completing, or missing vendor files, or whatever, are caused by not using the vendor files from TheMuppets on GitHub.
- Erase the vendor/samsung folder (if it exists)
- Edit the file .repo/local_manifests/roomservice.xml
- Add the line <project name="TheMuppets/proprietary_vendor_samsung" path="vendor/samsung" remote="github" /> in between the two top XML tags.
- Run the command "make clobber && repo sync" from your build root.
- Try your build again.