How do you uninstall Android OS v4.1.1?

Answer 1

Because the phone's OS is the backbone for it to operate properly, is the intent to uninstall it for a newer version of that OS, or an older version, or even a different OS entirely? If the phone has reached its service life for updates, and what you are seeking is an update, one of the options is to flash a custom ROM. Because Android is open-sourced, developers have put out various kinds of the Android OS, from "stock" Android (similar in experience on Nexus devices) to an OS with a skin (ie: TouchWiz or Sense), and can come in older versions of the OS (ex: Gingerbread) to the latest (ex: Jelly Bean).

I caution that if you choose to do this, any warranty you have on the phone would be voided. Also, if not done properly, you could run the risk of "bricking" the phone, meaning the phone might not function permanently. Knowing these risks, you can look at various developer sites in the internet to see how it is done.