A new update KB4073290 is now available for Windows 10 (v1709). This latest update will fix unbootable state for AMD devices.
On January 3, 2018, Microsoft rolled out update KB4056892 to fix the chip-level security flaw(Meltdown and Spectre) in Intel processors. However, it created problems like unbootable state for devices running AMD processors. This latest update will fix unbootable state for AMD devices.
Windows 10 update KB4073290 download Links
Currently, the update available for 64Bit systems only.