Microsoft has closed a backdoor left open in Windows RT even though the OS is pretty much dead in the water as Vole can’t be bothered with it any more.
This vulnerability in ARM-powered locked down Windows devices was left by Redmond programmers during the development process. Exploiting this flaw, a hacker could boot operating systems of his/her choice, including Android or GNU/Linux.
In fact the use of Linux on the tablets was pretty popular as Vole is killing the support for Surface RT tablets in 2017 and Windows RT 8.1 in 2018. This means that if the tablet is going to be any use, users will have to run something different on them.
A spokesVole described the backdoor as a security vulnerablity and fixed it accordingly. If you are planning to install some other operating system on your Windows RT tablet, avoid the lastest update. Of course chances are you are too late.