Standard Windows RT 8.1 installation media requires Secure Boot and a specific Microsoft signature. A "patched" ISO has been modified using tools like RTGetDown or Cygwin-based signature bypass scripts to allow what is known as "unsigned code execution."
There’s no legitimate product to review. Downloading a “Windows RT 8.1 patched ISO” is unsafe and unsupported. If you have an RT device, stick with the official OS (or consider a Linux ARM distro if available for your hardware). windows rt 81 iso patched
Cons / Risks