1. A method for updating a microcode image in a memory, the method comprising: responsive to initiation of an update process, checking a validity indicator to determine whether the microcode image in the memory is valid; responsive to the microcode image being valid, setting the validity indicator to indicate that the microcode image is invalid; responsive to the microcode image being valid, allowing the update process to update the microcode image to form an updated microcode image; determining whether the updated microcode image is valid; and setting the validity indicator to indicate that the microcode is valid if the updated image is valid, wherein the validity indicator is checked during booting of a data processing system to determine whether to load the microcode image.