Windows 10 build 9780

Windows 10 build 9780 is a pre-Technical Preview build of Windows 10. This build was leaked on or a little before 2019-01-26. This build is currently the earliest leaked build of Windows 10, and due to its earliness it is identified as Windows 8.1 in many areas and still has kernel version 6.3. It can also boot on current date due to it being in the fbl_partner branch. The product key is not known and a Windows 8.1 retail serial will not work. Therefore, the ei-cfg bypass must be used to install this build.