Limitations
WIMBoot is available for client editions of Windows 8.1 with Windows 8.1 Update only (not server versions). All architectures are supported, including amd64, x86, and ARM. Some enterprise deployment tools do not support WIMBoot.
WIMBoot is available only for UEFI-based PCs running in UEFI mode (legacy BIOS-compatibility mode isn't supported).
WIMBoot is supported for solid-state drives and eMMC (Windows HCK compliant) drives. WIMBoot isn't supported on traditional drives that contain rotational components, or on hybrid drives that contain both solid-state and rotational drive components. WIMBoot works by taking advantage of the capability of solid-state drives to access different areas of the hard drive quickly.
It's OK to have a secondary drive attached to the PC, and the secondary drive can contain rotational components. But the WIMBoot image and pointer files must all be located on the primary solid-state or eMMC drive.
Some backup, antivirus, and encryption tools aren’t compatible with WIMBoot images.
November 2014: Windows 8.1 Update PCs configured with WIMBoot will not receive November Update (KB3000850).
To save drive space, WIMBoot devices will only receive the following types of updates from Windows Update:
Critical updates that keep the system or programs running.
Security updates and security advisory updates.
Users can still manually download and install updates from the Microsoft Download Center.
WIMBoot is not recommended on systems with fixed internal storage of more than 32GB.