Windows 8.1 build 9477 (fbl partner out21)

Windows 8.1 build 9477 (fbl_partner_out21) is an unconfirmed build of Windows 8.1. It is a later compile of build 9477 under a different partner branch which is only known to exist in the ARM architecture. Only one image of this build exists on Chinese website BetaWorld. It was supposedly uploaded to the aforementioned site on 4 May 2019, but at the moment this cannot be confirmed or refuted as it is not publicly available.