2 Troubleshooting Procedures 2.4 System Board Troubleshooting Table 2-4 Debug port (Boot mode) error status (1/8) D port status Inspection items Details
Permission of A20 and Clear of
software reset bit
Prohibition of APIC
Initialization of MCHM
Initialization of ICHM
Initialization of Super I/O
Initialization of debug port
Dummy read of 3rd Bus data
PIT CH0 initialization (for
HOLD_ON)
BIOS rewrite factor flag
initialization
Transition to protected mode
Boot block checksum (skip when returned
to S3) (halts when error)
F000h
CHECK SUM CHECK
Checksum other than boot block (skip
when returned to S3)
F001h EC/KBC rewrite check
If “rewrite” is requested, go to
“BIOS rewrite process”.
Transition of process to System
BIOS IRT when returned to S3)
Key input
Check of Tilde key, Tab key if a key is
pressed
F002h BIOS rewrite request check
BIOS rewrite request check if
Checksum check error occurred
on except Boot Block or rewrite
is required by user. “BIOS
rewrite process”.
F003h Transits to System BIOS IRT
BIOS rewrite
Initialization of ICHM. D31
DRAM configuration
Permission of cache (L1 cache
only)
Memory clear
Transition to real mode and copy
of BIOS to RAM
QOSMIO G20 Maintenance Manual (960-511) [CONFIDENTIAL] 2-21