I am an old school PC user and have owned a Android phone since 2011. I started out with an LG running 2.2 Froyo and are familiar 2.2 Froyo, 2.3 Gingerbread, 4.0 ICS and KK and Lollipop; but I've never done any modifications to these operating systems aside from rooting a couple. I know the basics of how ROMing and mods are done; like rooting, custom bootloader, USB debugging etc But I've never done it. My question is why is it so hard to get/make ROMS for Android devices? Why does each OS have to be custom built and flashed as a ROM instead of being able to load a single disk image and have it " install " like Windows on a PC? I've had so many phones and tablets that were stuck on an outdated OS only to be told that no new ROMS were ever made and I was SOL. on a desktop you load the OS disk which is a full image of Windows/Linux/ OS X, and the installer program loads in RAM, finds and installs hardware drivers, then flashes to hard disk/ flash drive. If drivers are not available then you are prompted to install them from a separate disk during OS install. Even without drivers the computer can still display video in 16 bit legacy mode. All basic hardware works without drivers like keyboard, serial/parallel port, disk drives etc all work in legacy mode without drivers??