Introduction
1230B0026701
1-9
Checkpoint
Description
D5
Bootblock code is copied from ROM to lower system memory and control is given to
it. BIOS now executes out of RAM.
D6
Both key sequence and OEM specific method is checked to determine if BIOS
recovery is forced. Main BIOS checksum is tested. If BIOS recovery is necessary,
control flows to checkpoint E0. See Bootblock Recovery Code Checkpoints section
of document for more information.
D7
Restore CPUID value back into register. The Bootblock-Runtime interface module is
moved to system memory and control is given to it. Determine whether to execute
serial flash.
D8
The Runtime module is uncompressed into memory. CPUID information is stored in
memory.
D9
Store the Uncompressed pointer for future use in PMM. Copying Main BIOS into
memory. Leaves all RAM below 1MB Read-Write including E000 and F000 shadow
areas but closing SMRAM.
DA
Restore CPUID value back into register. Give control to BIOS POST
(ExecutePOSTKernel). See POST Code Checkpoints section of document for more
information.
Table 1-6 Bootblock Recovery Code Checkpoints
Checkpoint Description
E0
Initialize the floppy controller in the super I/O. Some interrupt vectors are initialized.
DMA controller is initialized. 8259 interrupt controller is initialized. L1 cache is
enabled.
E9
Set up floppy controller and data. Attempt to read from floppy.
EA
Enable ATAPI hardware. Attempt to read from ARMD and ATAPI CDROM.
EB
Disable ATAPI hardware. Jump back to checkpoint E9.
EF
Read error occurred on media. Jump back to checkpoint EB.
E9 or EA
Determine information about root directory of recovery media.
F0
Search for pre-defined recovery file name in root directory.
F1
Recovery file not found.
F2
Start reading FAT table and analyze FAT to find the clusters occupied by the
recovery file.
F3
Start reading the recovery file cluster by cluster.
F5
Disable L1 cache.
