Windows Phone 8.1 build 12075

Windows Phone 8.1 build 12075 is a build of Windows Phone 8.1. It was leaked on 2020-01-03 by gus33000. It is based on Windows 8.1 build 9379.

Bugs

 * The NTFS driver is heavily unstable in this build, which may cause the following bugs:
 * While installing, this build has a high chance of wiping the eMMC of the device you install it on.
 * If you install the build, it will most likely corrupt the NTFS file descriptor, making it look as if there are 0 files on the drive.
 * This build is capable of writing garbage data at a random location on the eMMC if boot fails. This includes the UEFI and the bootloader. If this happens, you will need to re-flash the eMMC.

Particularities
This build of Windows Phone 8.1 incorporates many features rumored at the time, such as:


 * A Notification Center application
 * The ability to sort the application list by most used
 * A couple new versions of some system apps marked with a "z" in front of them
 * An early version of Cortana, Microsoft's own Digital Assistant

Sadly the version of Cortana included cannot be used anymore nor seen because the servers for Microsoft Account login used by this build have been taken offline.