Compaq BIOS Post Codes
- 00 - Initialize flags, MSW,IDTLIN
- 01 - Read manufacturing jumper
- 02 - 8042 received read command
- 03 - No response from 8042
- 04 - Look for ROM at E000
- 05 - Look for ROM at C800
- 06 - Normal CMOS reset code
- 08 - Initialize 8259,80287
- 09 - Reset code in CMOS byte
- 0A - Vector vis 40:67 reset function
- 0B - Vector vis 40:67 with E01 function
- 0C - Boot reset function
- 0D - Test #2 8254 PIT counter 0
- 0E - Test #2 8254 PIT counter 2
- 0F - Warm boot
- 10 - PPI disabled, test 8254 PIT's 0 and 1
- 11 - Initialize (blast) VDU controller
- 12 - Clear screen; turn ON video
- 13 - Test time 0
- 14 - Disable RTC interrupts
- 15 - Check battery power
- 16 - Battery has lost power
- 17 - Clear CMOS Diags.
- 18 - Test base memory (First 128K)
- 19 - Initialize base memory
- 1A - Initialize VDU adapters
- 1B - The system ROM
- 1C - CMOS checksum
- 1D - DMA controller/page registers
- 1E - Test keyboard controller
- 1F - Test 286 protected mode
- 20 - Test real and extended memory
- 21 - Initialize time-of-day
- 22 - Initialize 287 coprocessor
- 23 - Test the keyboard and 8042
- 24 - Reset A20, set default CPU speed
- 25 - Test diskette subsystem
- 26 - Test fixed disk subsystem
- 27 - Initialize parallel printer
- 28 - Perform search for optional ROM's
- 29 - Test valid system configuration
- 2A - Clear screen
- 2B - Check for invalid time and date
- 2C - Optional ROM search
- 2D - Test timer 2
- 2F - Write to diagnostic byte
- 30 - Clear first 128K bytes of RAM
- 31 - Load interrupt vectors 70-77
- 32 - Load interrupt vectors 00-1F
- 33 - Initialize MEMSIZE and RESETWD
- 34 - Verify CMOS checksum
- 35 - CMOS checksum is not valid
- 36 - Check battery power
- 37 - Check for game adapters
- 38 - Check for Serial ports
- 39 - Check for parallel printer ports
- 3A - Initialize port and comm time-outs
- 3B - Flush keyboard buffer
- 40 - Save RESETWD value
- 41 - Check RAM refresh
- 42 - Start write of 128K RAM test
- 43 - Reset parity checks
- 44 - Start verify of 128K RAM test
- 45 - Check for parity errors
- 46 - NO RAM errors
- 47 - RAM error detected
- 50 - Check for dual frequency in CMOS
- 51 - Check CMOS VDU configuration
- 52 - Start VDU ROM search
- 53 - Vector to VDU option ROM's
- 54 - Initialize first display adapter
- 55 - Initialize second display adapter
- 56 - No display adapters installed
- 57 - Initialize primary VDU mode
- 58 - Start of VDU test (each adapter)
- 59 - Check existence of adapter
- 5A - Check VDU registers
- 5B - Start screen memory test
- 5C - End test of adapter, clear memory
- 5D - Error detected on an adapter
- 5E - Test the next adapter
- 5F - All adapters successfully tested
- 60 - Start of memory tests
- 61 - Enter protected mode
- 62 - Start memory sizing
- 63 - Get CMOS size
- 64 - Start test of real memory
- 65 - Start test of extended memory
- 66 - Save size memory (base, ext)
- 67 - 128K-option installed CMOS bit
- 68 - Prepare to return to real mode
- 69 - Back in real mode-successful
- 6A - Protected mode error during test
- 6B - Display error message
- 6C - End of memory test
- 6D - Initialize KB OK string
- 6E - Determine size to test
- 6F - Start MEMTEST
- 70 - Display XXXXXKB OK
- 71 - Test each RAM segment
- 72 - High order address test
- 73 - Exit MEMTEST
- 74 - Parity error on bus
- 75 - Start protected mode test
- 76 - Prepare to enter protected mode
- 77 - Test software exceptions
- 78 - Prepare to return to real mode
- 79 - Back in real mode-successful
- 7A - Back in real mode-error occurred
- 7B - Exit protected mode
- 7C - High order address test failure
- 7D - Entered cache controller test
- 7E - Programming memory cache
- 7F - Copy system ROM to high RAM
- 80 - Start of 8042 test
- 81 - Do 8042 self test
- 82 - Check result received
- 83 - Error result
- 84 - OK 8042, Init mode=5D
- 86 - Start test, reset keyboard
- 87 - Got acknowledge, read result
- 88 - Got result, check it
- 89 - Test for stuck keys
- 8B - Test keyboard interface
- 8A - Key seems to be stuck
- 8C - Got result, check it
- 8D - End of test, no errors
- 90 - Start of CMOS test
- 91 - CMOS seems to be OK
- 92 - Error on CMOS read,write test
- 93 - Start of DMA controller test
- 94 - Page registers seem to be OK
- 95 - DMA controller is OK
- 96 - 8237 initialization is complete
- 97 - Start of NCA RAM test
- A0 - Start of diskette tests
- A1 - FDC reset active (3F2h Bit 2)
- A2 - FDC reset inactive (3F2h Bit 2)
- A3 - FDC motor on
- A4 - FDC time-out error
- A5 - FDC failed reset
- A6 - FDC passed reset
- A8 - Start to determine drive type
- A9 - Seek operation initialized
- AA - Waiting for FDC seek status
- AF - Diskette tests complete
- B0 - Start of fixed drive tests
- B1 - Combo board not found-exit
- B2 - Combo controller failed-exit
- B3 - Testing drive 1
- B4 - Testing drive 2
- B5 - Drive error (error condition)
- B6 - Drive failed (failed to respond)
- B7 - No fixed drives-exit
- B8 - Fixed drive tests complete
- B9 - Attempt to boot diskette
- BA - Attempt to boot fixed drive
- BB - Boot attempt failed FD/HD
- BC - Jump to boot record
- BD - Drive error, retry booting
- BE - Weitek coprocessor test
- D0 - Entry to clear memory routine
- D1 - Ready to go to protected mode
- D2 - Ready to clear extended memory
- D3 - Ready to reset back to real mode
- D4 - Back in real mode
- D5 - Clear base memory
- DD - Built-in self-test failed
- E0 - Ready to replace E000 ROM
- E1 - Completed E000 ROM replacement
- E2 - Ready to replace EGA ROM
- E3 - Completes EGA ROM replacement