OK, this is going to be a question SIMILAR but NOT IDENTICAL to a lot of the questions asked here.
This is what I want to accomplish: modify build.prop whilst still be able to properly boot into the system WITHOUT reflashing/recovering anything at all.
The reason I'm using so much bolded texts is because all other questions I've both searched on this site and google in general focuses on how to salvage a bad situation e.g. "zomg how do I recover my system I swear I will not modify build.prop ever ever again!?" instead of how to actually modify build.prop, and, the rest is pretty much just "permission struggle": i.e. how to do chmod-ing.
With all the above out of the way, this is the problem I ran into:
I want to modify build.prop to adjust resolution, display density, orientation etc. to adjust my custom build android board for different machines (the type that you see on vending machines and at the airport). I can push my modded version to /system/, but after that the screen go completely dark and I lose the adb interface/connectivity.
After a little search work I figured it's because android has a rather rigorous security apparatus which checks if important files were modified and clearly my operation wouldn't get a free pass.
So how shall I accomplish what I want? If you must ask, this is the easiest way to adjust those settings (resolution etc.), modify it by running an APK is not an option.