Intel IA-32 - Manual (Page 438)

9-64 Vol. 3A
PROCESSOR MANAGEMENT AND INITIALIZATION
UPDATE_NUM_INVALID 99H The update number exceeds the maximum number of
update blocks implemented by the BIOS.
NOT_EMPTY 9AH The specified update block is a subsequent block in use to
store a valid microcode update that spans multiple blocks.
The specified block is not a header block and is not empty.
Table 9-18. Return Code Definitions (Contd.)
Return Code Value Description