Toshiba PORTEGE M400 - Manual (Page 69)

2.4 System board Troubleshooting 2 Troubleshooting
PORTEGE M400 Maintenance Manual (960-541) [CONFIDENTIAL] 2-21
Table 2-3 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 MCHM, ICHM
Initialization of Super I/O
Initialization of debug port
Dummy read of 3 rd Bus data
PIT CH0 initialization
(for HOLD_ON)
BIOS rewrite factor flag
initialization
Transition to protected mode
Boot block checksum (skipped when
returned to S3)
Halts when error occurs
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 When a key is pressed, check if it is Tilde
key or Tab key
F002h Initialization of SC Halts when error occurs D port=F003h or
04h
F006h BIOS rewrite request check If Checksum check error occurred on other
than Boot Block or rewrite is required by
user, go to “BIOS rewrite process”
Transits to system BIOS IRT
Initialization of ICHM. D31
DRAM configuration
Permission of cache (L1 cache only)
Memory clear
F007h
BIOS rewrite process
Transits to real mode and copies BIOS to
RAM