i have been looking at a lot of online descriptions of various Android emulators. but i want one that actually runs the real OS images that are normally run on Android ARM CPUs, as opposed to the one i looked at a few years ago that did some kind of x86 based fakery that didn't use real ARM code. it should be an emulator of actual ARM-based Android hardware with the ability to use selected files for any read-only memory and preload an OS from the upgrade images people can download for their devices. none of the emulators i have seen described get detailed enough to know what they really do in this respect.