1/14/2021
`
`Computer BIOS / POST Error Codes
`
`Computer BIOS / POST Error Codes
`
`Booting the Computer
`
`When you first apply power to a PC type computer, it begins running a firmware program stored in non-volatile memory in a
`chip on the motherboard. Newer systems use UEFI or the Unified Extensible Firmware Interface, but older systems use the
`BIOS (or Basic Input/Output System) defined by IBM in the early 1980s. The firmware performs some power-on self-test
`operations and detects the processor and memory. It then initializes various programmable devices which may have their
`own firmware. If all that succeeds, a system with BIOS emits a single beep to indicate success. Any problems encountered
`along the way cause other audible codes. This page lists those possible error codes, which vary by manufacturer.
`
`Only after this testing and initialization are completed can the system progress to loading
`and starting the full operating system. The stages of this operation are described below.
`
`POST
`
`The Power-On Self Test or POST first finds the CPU and then finds the memory.
`
`Initialization
`
`For much more on BIOS versus UEFI firmware
`and how the operating system boots and start
`services see my Linux booting page.
`
`For multibooting Windows versus OpenBSD or
`other operating systems, see my multiboot page.
`
`Start-up values are placed in programmable devices in this order: system board devices, then the video controller, then the
`I/O controller.
`
`One Beep is Good
`
`A typical BIOS on a system other than a laptop emits one beep when the POST and Initialization stages complete
`successfully. Other audible codes indicate errors.
`
`At this point the video card should be initialized and you should see the BIOS logo and some narrative output on the display
`as it tests the system memory that it detected.
`
`You will be told how to get into the BIOS setup, typically pressing <Escape> or <Delete> or <F2> or <F12> or some
`other key. Read and act quickly, as you have a rather short time to do this.
`
`Hardware Inventory
`
`The output is visible for just a very short time, but you may be able to notice as it detected the I/O controllers,
`inventoried the PATA and SATA disks, and listed other hardware devices by IRQ and possibly address.
`
`Booting the Operating System
`
`The BIOS then inventories the bootable devices in order according to the list in its configuration. Some potentially bootable
`
`
`
`
`devices may have no media present, such as the CD/DVD drive or the USB ports.
`RESERVE NOW
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`https://cromwell-intl.com/technical/bios.html
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`Patent Owner, Bot M8 LLC - Ex. 2035, p. 1
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`1/14/2021
`
`Computer BIOS / POST Error Codes
`For those bootable devices with media present — all the disks plus the populated removable media — it looks for the first
`one of those media with a valid boot block. This is the first 512-byte block on the media.
`
`This boot block is the system-wide Master Boot Record. It carries out the first stage of loading the operating system from
`storage into RAM and starting it. See the description of the operating system boot process for more details.
`
`A Phoenix BIOS chip is seen above and at right, near one corner of a system board next to the end of two unpopulated PCI
`bus slots.
`
`BIOS POST Beep Error Codes
`
`As mentioned above, one beep generally means that the POST and following stages found and initialized the CPU, memory,
`video and system board I/O interfaces. More than one beep means trouble, see the following tables.
`
`No beep at all might mean that POST or the initialization failed. Or it might simply mean that no speaker is attached to the
`system board!
`
`AMI / American Megatrends
`
`American Megatrends was founded in 1985 and is headquartered near Norcross, Georgia, part of the Atlanta metropolitan
`area.
`
`Code
`
`1 short
`
`2 short
`
`3 short
`
`4 short
`
`5 short
`
`6 short
`
`7 short
`
`8 short
`
`AMI
`
`Description
`
`All is good!
`
`Parity error in the first 64 kbytes of RAM.
`
`Memory error in the first 64 kbytes of RAM.
`
`Memory error in the first 64 kbytes of RAM, plus a non-functional timer.
`
`CPU error
`
`Keyboard controller error.
`
`CPU virtual mode exception error.
`
`Read/write error on video controller memory.
`
`1 long, 8 short Video controller display/retrace error.
`
`9 short
`
`10 short
`
`11 short
`
`ROM BIOS checksum error. This may be caused by the CMOS battery running down.
`
`CMOS shutdown read/write error. This is likely caused by the CMOS battery running down.
`
`L2 cache error.
`
`Phoenix Technologies
`
`https://cromwell-intl.com/technical/bios.html
`
`2/5
`
`Patent Owner, Bot M8 LLC - Ex. 2035, p. 2
`
`

`

`1/14/2021
`
`Computer BIOS / POST Error Codes
`Phoenix Technologies has been around since 1979, giving them plenty of time to add details. The BIOS
`goes through a series of tasks, writing a one-byte test-point error code to I/O port 0x80h at the start of each.
`For examples, 0x04 for the "Get CPU type" task, 0x0A for "Initialize CPU registers", 0x0B for "Enable CPU cache", and so
`on. Note that the tasks are not done in numerical order by error code.
`
`If an error is encountered, the BIOS attempts to initialize the video display and write the current code at the upper left of the
`screen. It also generates a beep code from the test point error code by:
`1. Break 8-bit error code into four 2-bit groups.
`2. Add 1 to each 2-bit value, forming a sequence of four digits each in the range 1 through 4.
`3. Emit that sequence of numbers as a series of beeps.
`
`For example, "Test 8742 Keyboard Controller" is task 0x22, so:
`0x22 = 00100010 --> 00 10 00 10 --> 0 2 0 2 --> 1 3 1 3
` convert to break into convert add 1 to each,
` binary 4 pieces to decimal that many beeps
`
`The following are among the possible Phoenix BIOS beep error codes:
`
`Phoenix
`
`Code Description
`
`1
`
`All is good!
`
`1-1-3-3 CPU failure
`
`1-1-3-4 CPU failure
`
`1-1-4-1 CPU failure
`
`1-2-2-1 Keyboard controller failure
`
`1-2-2-3 BIOS ROM checksum error
`
`1-3-1-1 DRAM memory refresh error
`
`1-3-1-3 Keyboard controller failure
`
`1-3-3-1 Memory failure
`
`1-3-3-2 Memory failure
`
`1-3-3-3 Memory failure
`
`1-3-4-1 Memory failure
`
`1-3-4-3 Memory failure
`
`1-4-1-1 Memory failure
`
`2-1-2-2 POST device initialization failure
`
`2-1-2-3 BIOS ROM copyright notice error
`
`2-2-3-1 Unexpected interrupt
`
`2-2-4-1 Memory failure
`
`Award
`
`Award Software International existed for just a couple of years, from its founding in 1996 until it was absorbed inthe
`Phoenix Technologies in mid 1998. On top of that, there were many versions of the Award BIOS and they were customized
`and supported by the system board manufacturers.
`
`There were some codes that seemed to be fairly standard, shown below.
`
`But seriously, if you have an Award BIOS then you have some old computing hardware. It's time to upgrade!
`
`AWARD
`
`Code
`
`1 long
`
`Description
`
`All is good!
`
`1 long, 2 short
`
`Video controller could not be initialized.
`
`https://cromwell-intl.com/technical/bios.html
`
`3/5
`
`Patent Owner, Bot M8 LLC - Ex. 2035, p. 3
`
`

`

`1/14/2021
`
`Computer BIOS / POST Error Codes
`
`Repeated beeping CPU or memory error, excessive CPU heat or mis-seated CPU or memory.
`
`IBM
`
`Speaking of antiquated hardware, IBM made PCs back in the early 1980s. Some early "PC compatible" hardware was
`designed by reverse-engineering, including the original IBM PC BIOS.
`
`Original IBM BIOS Codes
`
`Code
`
`1 long
`
`Description
`
`All is good!
`
`No beep, or
`continuous tone, or
`repeating short beet
`
`Loose card, low voltage or other basic electrical problem.
`
`2 short
`
`Initialization error. The error code will be displayed on the screen:
`
`Range Error is in...
`
`100—199 System board
`
`200—299 Memory
`
`300—399 Keyboard
`
`400—499 Monochrome display controller
`
`500—599 Color display controller
`
`600—699 Floppy disk drive or controller
`
`700—799 Math coprocessor
`
`900—999 Parallel port
`
`1000—1099 Second parallel port
`
`1100—1299 Asynchronous communication port
`
`1300—1399 Game port
`
`1400—1499 Printer
`
`1500—1599 Synchronous communication port
`
`1700—1799 Hard disk or controller
`
`1800—1899 XT expansion unit
`
`2000—2199 Bisynchronous communication port
`
`2400—2599 EGA/MCA system board video
`
`3000—3199 LAN adapter
`
`4800—4899 Internal modem
`
`7000—7099 Phoenix BIOS chips
`
`7300—7399 3.5" floppy disk drive
`
`8900—8999 MIDI adapter
`
`11200—11299 SCSI adapter
`
`21000—21099 SCSI fixed disk and controller
`
`21500—21599 SCSI CD-ROM
`
`1 long, 1 short
`
`System board problem
`
`1 long, 2 short, or
`1 long, 3 short
`
`Video controller problem
`
`3 long
`
`3270 keyboard adapter problem
`
`https://cromwell-intl.com/technical/bios.html
`
`4/5
`
`Patent Owner, Bot M8 LLC - Ex. 2035, p. 4
`
`

`

`1/14/2021
`
`Computer BIOS / POST Error Codes
`
`How Linux Boots EIDE / PATA / SATA / USB Cable Pinouts
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