Toshiba Portege R400 Series, Maintenance Manual

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2 Troubleshooting Procedures
PORTEGE R400 Maintenance Manual (960-623) [CONFIDENTIAL] 2-21
Table 2-4 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
（
when
returned to S3)
Key input
F001H
When a key is pressed, check if it is
Tilde key or Tab key
F002H
Initialization of SC
F003H
HLT
F004H HLT
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”.
Transits to System BIOS IRT
BIOS rewrite process Initialization of ICHM. D31
DRAM configuration
Permission of cache (L1 cache only)
Memory clear
F007H
Transition to real mode and copy of BIOS to
RAM