2.4 System Board Troubleshooting 2 Troubleshooting Procedures
PORTEGE R500 Maintenance Manual (960-634) [CONFIDENTIAL] 2-19
Table 2-5 Debug port (Boot mode) error status (1/10)
D port status Inspection items Details
Permission of A20 and Clear of
software reset bit
Prohibition of APIC
Initialization of MCH and ICH
Initialization of Super I/O
Initialization of debug port
Boot block
Dummy read of 3rd Bus data
Only 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)
EC/KBC rewrite check If “rewrite” is requested, go to “BIOS rewrite process”
Transition to system BIOS IRT（w hen
returned to S3)
Key input
F001H
When a key is pressed, check if it is
Tilde key or Tab key
F002H Initialization of SC
F005H
F006H BIOS rewrite request check If Checksum check error occurred on except
Boot Block or rewrite is required by user, go to
“BIOS rewrite process”.
F007H BIOS signature check
Transits to System BIOS IRT
Initialization of ICHM. D31
DRAM configuration
Permission of cache (L1 cache only)
F008H
BIOS rewrite process
Memory clear
F009H Transition to real mode and copy of BIOS to
RAM