B-3
Appendix B: AMIBIOS POST Checkpoint Codes
B-3 Uncompressed Initialization Codes
The following runtime checkpoint codes are listed in order of execution.
These codes are uncompressed in F0000h shadow RAM.
Checkpoint Code Description
03h The NMI is disabled. Next, checking for a soft reset or a power on
condition.
05h The BIOS stack has been built. Next, disabling cache memory.
06h Uncompressing the POST code next.
07h Next, initializing the CPU and the CPU data area.
08h The CMOS checksum calculation is done next.
0Ah The CMOS checksum calculation is done. Initializing the CMOS status
register for date and time next.
0Bh The CMOS status register is initialized. Next, performing any required
initialization before the keyboard BAT command is issued.
0Ch The keyboard controller input buffer is free. Next, issuing the BAT
command to the keyboard controller.
0Eh The keyboard controller BAT command result has been verified. Next,
performing any necessary initialization after the keyboard controller BAT
command test.
0Fh The initialization after the keyboard controller BAT command test is done.
The keyboard command byte is written next.
10h The keyboard controller command byte is written. Next, issuing the Pin 23
and 24 blocking and unblocking command.
11h Next, checking if <End or <Ins> keys were pressed during power on.
Initializing CMOS RAM if the

Initialize CMOS RAM in every boot

AMIBIOS POST option was set in AMIBCP or the <End> key was pressed.
12h Next, disabling DMA controllers 1 and 2 and interrupt controllers 1 and 2.
13h The video display has been disabled. Port B has been initialized. Next,
initializing the chipset.
14h The 8254 timer test will begin next.
19h The 8254 timer test is over. Starting the memory refresh test next.
1Ah The memory refresh line is toggling. Checking the 15 second on/off time
next.
2Bh Passing control to the video ROM to perform any required configuration
before the video ROM test.
2Ch All necessary processing before passing control to the video ROM is done.
Looking for the video ROM next and passing control to it.
2Dh The video ROM has returned control to BIOS POST. Performing any
required processing after the video ROM had control.
23h Reading the 8042 input port and disabling the MEGAKEY Green
PC feature next. Making the BIOS code segment writeable and
performing any necessary configuration before initializing the
interrupt vectors.
24h The configuration required before interrupt vector initialization
has completed. Interrupt vector initialization is about to begin.