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AMIBIOS is a personal computer BIOS developed by [[American Megatrends|AMI (American Megatrends)]], which has bought it's rights from Access Methods Inc. in around 1986. Earliest known mentions of AMIBIOS are from 1985, with [[AMIBIOS Rev-X2-03|the earliest known version]] likely being released around that time.
'''AMIBIOS,''' commonly stylized as '''AMI BIOS''', is an IBM PC-compatible BIOS firmware. It was initially released by [[Access Methods Inc.]] in 1985 and later acquired and developed by [[American Megatrends]] (now AMI Inc.). It is also one of the first IBM PC-compatible BIOS firmware that were mass licensed for clone systems, released shortly after the competing [[PhoenixBIOS]]. Similar to that, it was also reverse engineered under a clean room solution to avoid infringement of IBM's copyright.


While it is still used on some current day industrial/embedded platforms (such as ones based on the Vortex86 SoC), it has been fully phased out on modern consumer platforms in favor of (U)EFI-based solutions such as [[AMI Aptio|Aptio]] (which is it's successor), [[InsydeH2O]] and [[Phoenix SecureCore]]. However, most older instances of Aptio released still included an embedded version of [[AMIBIOS 8]] as a component module for CSM/legacy boot. With CSM being discontinued by Intel in 2020 however, the module is no longer present.<ref>https://www.intel.com/content/www/us/en/content-details/630266/removal-of-legacy-boot-support-for-intel-platforms-technical-advisory.html | Note: Although this document was published in 2023, it clearly mentions legacy boot being discontinued in 2020.</ref>
Its latest mainstream version, [[AMIBIOS 8]], was phased out on most platforms released after 2010, in favor of modern UEFI-based firmware solutions (such as its successor [[AMI Aptio]] or the competing [[InsydeH2O]]). Despite this, it is still used on some industrial systems (such as the ones with the [[wikipedia:Vortex86|Vortex86]] SoC) that are based on a legacy architecture. It is also commonly used on newer motherboards made for legacy platforms, especially [[wikipedia:LGA_775|LGA 775]] and [[wikipedia:LGA_1156|1156]] sockets.  


== Purchase from Access Methods ==
Earlier instances of [[AMI Aptio]] contained an embedded version of [[AMIBIOS 8]] as a component module for legacy boot (CSM) only mode (not to be confused with UEFI boot mode with CSM). However, since CSM was discontinued by Intel in 2020<ref>https://www.intel.com/content/www/us/en/content-details/630266/removal-of-legacy-boot-support-for-intel-platforms-technical-advisory.html | Note: Although this document was published in 2023, it clearly mentions legacy boot being discontinued in 2020.</ref>, this mode was removed along with its module. Although most newer instances still support UEFI boot mode with CSM support, this mode does not utilize the mentioned module.
 
== Acquisition from Access Methods Inc. ==
''Main page: [[American Megatrends]]''
''Main page: [[American Megatrends]]''


Access Methods Inc. created AMIBIOS in 1985. Same year, Access Methods' owners (Subramonian Shankar and Pat Sarma) found a new company from the funds raised with it. It was called Quintessential Consultants Inc. (QCI), which then got renamed to American Megatrends Inc. (AMI) to keep the "AMIBIOS" acronym. American Megatrends then bought AMIBIOS from Access Methods next year.
Access Methods Inc., a joint venture by Subromanian Shankar and Pat Sarma, released the first version of AMIBIOS in 1985.<ref>https://twit.tv/shows/triangulation/episodes/226</ref> Shortly after and due to legal issues, the owners found a new company with the funds raised by this joint venture. This venture was founded as Quintessential Consultants Inc. (QCI) and later renamed to American Megatrends Inc. (AMI) to keep the "AMIBIOS" acronym. The venture then acquired AMIBIOS from Access Methods next year.<ref>https://www.youtube.com/watch?v=5jYX3sL08Xs</ref>


== List of known versions ==
== List of known versions ==
All versions made before AMI Plus BIOS were released by Access Methods, although some of these versions later received new cores (revisions) from American Megatrends and those had their copyright (instead of Access Methods').
All versions before [[AMI Plus BIOS]] were initially released by Access Methods. Therefore, on most instances (ROMs) for these versions, the copyright strings mention "Access Methods Inc.". However, some of these versions were later continued to be developed by American Megatrends after the acquisition. Therefore, on these newer instances, the strings may sometimes mention "American Megatrends Inc." instead, despite not being initially released by them.  


Almost all instances of versions from AMIBIOS 2.2x to AMIBIOS 6 and AMIBIOS 07.00.10 can be identified by the date in the POST string, which (unlike on AMIBIOS 07.00.xx and 8) is actually fixed to the initial AMIBIOS release date. However these dates were occasionally modified by OEMs/motherboard manufacturers to reflect the BIOS compile or revision release date instead, especially during the pre-WinBIOS (AMIBIOS 4) era. Since AMIBIOS 07.00.xx (excluding AMIBIOS 07.00.10), the date in the string reflects the specific revision's compile date instead and therefore cannot be used to determine the initial release date of the AMIBIOS version.
In most cases, the ROMs of all versions from [[AMIBIOS 2.2x|AMIBIOS 2.x]] to [[AMIBIOS 6]] and also [[AMIBIOS 7|AMIBIOS 7 (07.00.10)]] can be identified by the six-digit date shown in the identification string, which is displayed during the Power-On Self Test (POST). This is because these dates are actually fixed to the initial release date of the AMIBIOS version. However, occasionally, some [[wikipedia:Original_equipment_manufacturer|OEMs]] modified these dates to reflect the ROM compile or release date instead, especially on early versions before [[AMI WinBIOS|AMI WinBIOS (AMIBIOS 4)]]. The ROMs for [[AMIBIOS 07.00.xx|AMIBIOS 07.00.xx (07.00.00)]] and [[AMIBIOS 8]] also cannot be identified this way, as the date in their strings is actually fixed to the ROM compile date instead of the AMIBIOS version release date.


'''Notice:''' Due to lack of proper information and reference guides, names for all versions made before AMI Hi-Flex BIOS are assumed based on a few unofficial sources online and they may not reflect the actual BIOS version names. As more information is discovered, these may be corrected.
'''Please note that the following information may not be fully correct for versions released before AMI Hi-Flex BIOS, as their names had to be assumed due to lack of information and other references.'''
{| class="wikitable" style="width:100;%"
{| class="wikitable" style="width:100;%"
|+List of known AMIBIOS versions
!Version name
!Version name
!First release date
!First release date
!POST screen (if available)
!POST screen (if available)
!Known core dates
!Notes
!Notes
|-
|-
|[[AMIBIOS Rev-X2-03|''"Rev-X2-03" (AMIBIOS 2.03?)'']]
|[[AMIBIOS 1.x]]
|Most likely 1985 or early 1986
|1985
|[[File:AMIBIOS_Rev-X2-03_POST.png|300px]]
|''Not available''
|Possibly the earliest known version. AMIBIOS 2.03 is a possible name, although unconfirmed.
|
|The first version of AMIBIOS
|-
|-
|[[AMIBIOS 2.2x|AMIBIOS 2.2x(?)]]
|[[AMIBIOS 2.x]]
|1986
|1986
|[[File:AMIBIOS_2.2x_POST.png|300px]]
|[[File:AMIBIOS_2.2x_POST.png|300px]]
|The name is assumed based on unofficial information and may not be correct.
|
|The name is assumed based on information from the unofficial MR BIOS website<ref>https://mrbios.com/techsupport/award/postcodes.htm | "AMI BIOS 2.2x" section</ref>
|-
|-
|[[AMI Plus BIOS|AMI Plus BIOS(?)]]
|[[AMI Plus BIOS]]
|1987
|1987
|[[File:AMI_Plus_BIOS_POST.png|300px]]
|[[File:AMI_Plus_BIOS_POST.png|300px]]
|The name is assumed based on unofficial information and may not be correct. Sometimes (unofficially) also called AMI Pre-Color BIOS by some enthusiasts as it has a black and white setup utility and was released before Hi-Flex BIOS (which is often also unofficially called AMI Color BIOS, due to it's colorful setup utility).
|
|Name assumed based on information from the unofficial MR BIOS website<ref>https://mrbios.com/techsupport/award/postcodes.htm | "AMI Plus BIOS" section</ref>. Commonly nicknamed "AMI Pre-Color BIOS" due to its monochrome setup utility, which is the predecessor of [[AMI Hi-Flex BIOS|Hi-Flex BIOS']] setup utility (which is in color).
|-
|-
|[[AMI Hi-Flex BIOS]]
|[[AMI Hi-Flex BIOS]]
|1990
|November 1990
|[[File:AMI_Hi-Flex_BIOS_POST.png|300px]]
|[[File:AMI_Hi-Flex_BIOS_POST.png|300px]]
|Not to be confused with the Hi-Flex Setup Utility on AMIBIOS 6 and 07.00.10, which was named after it. Unofficially also called AMI Color BIOS by some enthusiasts (due to its colorful setup utility). It was likely also called AMIBIOS 3 internally, although unconfirmed.
|
|Not to be confused with the Hi-Flex Setup Utility in [[AMIBIOS 6]] and [[AMIBIOS 07.00.10]]. Commonly nicknamed "AMI Color BIOS" or "AMIBIOS Color" due to its colorful setup utility. Possibly also called AMIBIOS 3 internally, although unconfirmed.
|-
|-
|[[AMI WinBIOS|AMI WinBIOS (AMIBIOS 4)]]
|[[AMI WinBIOS|AMI WinBIOS (AMIBIOS 4)]]
|1993
|December 1993
|[[File:WinBIOS_POST_screen.png|300px]]
|[[File:WinBIOS_POST_screen.png|300px]]
|Often referred to as AMI WinBIOS, not to be confused with the WinBIOS Setup Utility on AMIBIOS 6 (which was named after it). Often known with the core date <code>121593</code> (December 15, 1993) in string, however other core dates also exist.
|
|Not to be confused with the WinBIOS Setup Utility in [[AMIBIOS 6]]
|-
|-
|[[AMIBIOS 5]]
|[[AMIBIOS 5]]
|1994
|October 1994
|[[File:AMIBIOS 5 101094.png|300px]]
|[[File:AMIBIOS 5 101094.png|300px]]
|Visually looks almost identical to AMIBIOS 4, although contains initial bug fixes and new features. Often known with the core date <code>101094</code> (October 10, 1994) in string.
|10/10/94
|
|-
|-
|[[AMIBIOS 6]]
|[[AMIBIOS 6]]
|1995
|July 1995
|[[File:AMIBIOS 6 POST screen.png|300px]]
|[[File:AMIBIOS 6 POST screen.png|300px]]
|Often known with the core date <code>071595</code> in string, however other core dates also exist.
|07/15/95
07/15/97
 
07/15/99
|Also known as AMIBIOS 97 (1997), AMIBIOS 98 (1998) and AMIBIOS 99 (1999)<ref>https://web.archive.org/web/19970623225759/http://www.amibios.com/amibios.html</ref><ref>https://web.archive.org/web/19991012065711fw_/http://ami.com/amibios/bios.platforms.desktop.html</ref>
|-
|-
|[[AMI eBIOS Version 1]]
|[[AMIBIOS 07.00.xx|AMIBIOS 07.00.xx (07.00.00)]]
|''Unknown''
|''Not available.''
|Currently no information is available and it might not actually exist, however it is assumed to exist due to the existence of [[AMI eBIOS 02.00.xx|eBIOS 02.00.xx]].
|-
|[[AMIBIOS 07.00.xx|AMIBIOS 07.00.xx / 07.00.00]]  
|1999
|1999
|[[File:AMIBIOS 07.00.xx POST.png|300px]]
|[[File:AMIBIOS 07.00.xx POST.png|300px]]
|Not to be confused with AMIBIOS 07.00.10 [with date <code>040201</code> (April 2, 2001) in string]. Probably an early development release of [[AMIBIOS 8]], which might have initially been called AMIBIOS 7.
|''Not used''
|Officially named AMIBIOS V7.0<ref>https://web.archive.org/web/20000607010157fw_/http://www.ami.com/y2k_ami.html | "V.7.0" is listed as an AMIBIOS version, which must be 07.00.xx as 07.00.10 was not yet released at the time</ref>, not to be confused with [[AMIBIOS 7|AMIBIOS 7 (07.00.10)]]. Likely a pre-release version of [[AMIBIOS 8|AMIBIOS 8 (BigBIOS)]].  
|-
|-
|[[AMI eBIOS 02.00.xx]]
|[[AMIBIOS 7|AMIBIOS 7 (07.00.10)]]
|2000 or 1999
|April 2001
|[[File:RCH31-18b.jpg|300px]]
|Assumed to be a variant of [[AMIBIOS 07.00.xx]] for embedded systems. Not much else is known about it.
|-
|[[AMIBIOS 07.00.10|AMIBIOS 7 (07.00.10)]]
|2001
|[[File:AMIBIOS 07.00.10 POST.png|300px]]
|[[File:AMIBIOS 07.00.10 POST.png|300px]]
|Not to be confused with AMIBIOS 07.00.xx/07.00.00. Often known with the core date <code>040201</code> (April 2, 2001) in string. Assumed to be an update based on the AMIBIOS 6 codebase.
|04/02/01
|-
|Also named AMIBIOS 07.00T. Possibly an update for AMIBIOS 6 for meeting the [[wikipedia:PC_System_Design_Guide#PC_2001|PC 2001]] requirements.
|[[64-Bit AMIBIOS Version 1]]
|2001(?)
|''Not available.''
|Currently no information is available and it might not actually exist, however it is assumed to exist due to the existence of  [[64-Bit AMIBIOS 02.00.00]].
|-
|-
|[[AMIBIOS 8]]
|[[AMIBIOS 8]]
|2001
|October 2001
|[[File:AMIBIOS 8 POST screen (large logo).png|300px]]
|[[File:AMIBIOS 8 POST screen (large logo).png|300px]]
|Last standalone version of AMIBIOS. Most likely the final product for AMIBIOS 07.00.xx/07.00.00. Although first released in 2001, it was not used widely until a couple years later.
|''Not used''
|-
|Last commercial version of AMIBIOS. Codenamed "BigBIOS".
|[[64-Bit AMIBIOS 02.00.00]]
|2003(?)
|''Not available.''
|Assumed to be a variant of AMIBIOS 8 or 07.00.xx for Itanium based servers. Only known instance is on the SuperMicro MBD-i2DML-8G2-O Intel Itanium motherboard.
|-
|-
|[[AMIBIOS 9]]
|[[AMIBIOS 9]]
|''Unknown''
|''Unknown''
|''Not available.''
|''Not available.''
|Used on Microsoft Hyper-V. Assumed to be a special version or code fork for it, or possibly the name given to emulated BIOS for CSM mode in AMI Aptio.
|''Not used''
|Used in Microsoft Hyper-V. Possibly the name given to the BIOS emulation component for CSM/legacy only mode in [[AMI Aptio]].
|}
|}


== BIOS string ==
== ROM identification string ==
The BIOS string for AMIBIOS was first introduced with AMIBIOS 2.2x for easy identification of each BIOS release and is often seen during POST at the very bottom of the screen. The string format was changed a couple times with new core versions of AMIBIOS. Known codes for some identification sections are given in the List of codes for BIOS strings section.
The ROM identification string was first introduced with [[AMIBIOS 2.x]] and is often located at the bottom left of the POST screen. With this string, many useful details regarding the BIOS ROM can usually be gathered, such as the ROM size, chipset, motherboard manufacturer and sometimes even the AMIBIOS version. The string is formatted into sections with each containing different information regarding the ROM. The known codes for these sections are listed in [[Document:AMIBIOS string codes|the list of codes for BIOS strings]] (also available at the bottom of this page). The string format has been changed various times with some new releases of AMIBIOS.


=== AMIBIOS 2.2x ===
=== AMIBIOS 2.x ===
'''MMMM:''' Manufacturer/OEM identification code, '''SSSSSS:''' BIOS subcore release date
<code>MMMM-SSSSSS</code>


<code>MMMM-SSSSSS</code>
* '''MMMM:''' OEM identification code
* '''SSSSSS:''' AMIBIOS version release date (occasionally modified to reflect the ROM compile date instead)


'''Example string''': 1406-061286
'''Example string''': 1406-061286


This string is for a 06/12/86 (June 12, 1986; date is in American format) dated subcore BIOS for Flying Triumph Co. Ltd. ("1406").
This string is for an AMIBIOS 2.x version released on June 12, 1986 ("061286") for Flying Triumph Co. Ltd. ("1406").


=== AMI Plus BIOS ===
=== AMI Plus BIOS ===
'''D:''' CMOS setup type, '''CCC:''' Chipset type, '''MMMM:''' Manufacturer/OEM identification code, '''SSSSSS:''' BIOS subcore release date, '''KK:''' Keyboard controller (KBC) ID (with second character indicating the model).
<code>DCCC-MMMM-SSSSSS-KK</code> (single digit CMOS setup type)


<code>DCCC-MMMM-SSSSSS-KK</code>
<code>DDCCC-MMMM-SSSSSS-KK</code> (two digit CMOS setup type)


'''Note:''' The CMOS setup type code can be two characters for "DE" in case the BIOS contains both extended setup and built-in diagnostics.
* '''D:''' CMOS setup type
** This section can also be two characters long for "DE" if the ROM contains both built-in diagnostics and an extended setup.
* '''CCC:''' Chipset type
* '''MMMM:''' OEM identification code
* '''SSSSSS:''' AMIBIOS version release date (occasionally modified to reflect the ROM compile date instead)
* '''KK:''' Keyboard controller ID (with second character indicating the model).


'''Example string''': D286-1277-043089-K0
'''Example string''': D286-1277-043089-K0


This string is for a 04/30/89 (April 30, 1989; date is in American format) dated subcore AMI Plus BIOS with regular CMOS setup and built-in diagnostics ("D") for a machine with a discrete i286 logic ("286") and a default/unknown keyboard controller (K"0") made by Trangg Bow Co. ("1277").
This string is for an AMI Plus BIOS version released on April 30, 1986 ("043089") with built-in diagnostics ("D") for a machine with a discrete logic chipset for [[wikipedia:Intel_80286|80286]] ("286") and a default/unknown keyboard controller (K"0") for Trangg Bow Co. ("1277").
 
=== AMI Hi-Flex BIOS and later versions ===
This format is also used by the earlier instances of [[AMI Aptio]] with the CSM module.
 
<code>CR-VVVV-00MMMM-FFFFFFFF-SSSSSS-DDDDDDDD-Project-Y2KC-K</code>


=== Later BIOS versions ===
* '''C:''' Processor architecture
'''C:''' Processor architecture, '''R:''' ROM size, '''MMMM:''' Manufacturer/OEM identification code, '''FFFFFFFF:''' BIOS feature identification (often 00101111), '''SSSSSS:''' BIOS compile date OR subcore release date, '''DDDDDDDD:''' BIOS identifier, '''Project:''' BIOS project ID (no maximum characters), '''K:''' Keyboard controller (KBC) ID
* '''R:''' ROM size
* '''MMMM:''' OEM identification code
* '''FFFFFFFF:''' BIOS feature identification
** Usually "00101111" which is the default.


<code>CR-VVVV-00MMMM-FFFFFFFF-SSSSSS-DDDDDDDD-Project-K</code>
* '''SSSSSS:''' ROM compile date ([[AMIBIOS 07.00.xx]] and [[AMIBIOS 8]]) or the AMIBIOS version release date (all other versions, excluding OEM modifications)
** '''Note:''' Even on versions using the initial release date, this section was occasionally modified by the OEM to reflect the ROM release date instead.
* '''DDDDDDDD:''' BIOS identifier (usually the chipset)
* '''Project:''' Internal BIOS project ID
** Only used on later revisions of [[AMIBIOS 6]] and later versions.
* '''Y2KC:''' Most likely an indicator for Year 2000 (Y2K) compatibility
** Only used on [[AMIBIOS 07.00.xx]] and [[AMIBIOS 8|8]].
* '''K:''' Keyboard controller ID
** Not used on [[AMIBIOS 7|AMIBIOS 7 (07.00.10)]] and [[AMIBIOS 8|8]].


'''Note:''' The project ID section is only present on late AMIBIOS 6 and later releases. The keyboard controller ID is also not used since AMIBIOS 07.00.xx.
'''Example string''': 61-0530-001169-00101111-071595-440BX/ZX-1AAET006-R


'''Example string''': 61-1108-001169-00101111-071595-440BX/ZX-1440B000-H
This string is for a 05.30 version ("0530") 128 KB ("1")* size AMIBIOS 6 ROM ("071595", initial release date for AMIBIOS 6) for 686 architecture processors ("6") with Intel 440BX or ZX chipset ("440BX/ZX") and an AMIKEY '94 clone keyboard controller ("R") for project ID 1AAET006 of MSI ("1169").


This string is for a 11.08 revision ("1108") 128 KB ("1") size AMIBIOS 6 ("071595", main subcore for it) for a motherboard for 686 architecture processors ("6") with Intel 440BX or 440ZX chipset ("440BX/ZX") and an AMIKEY-2 clone keyboard controller ("H") made by MSI ("1169").
<nowiki>*</nowiki> The BIOS ROM size is actually 256 KB in this specific case, the 128 KB size specified in the string is erroneous. This also proves that the string is not always fully accurate..


=== List of known codes for BIOS strings ===
=== List of known codes for sections of the ROM identification string ===
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<div class="toccolours mw-collapsible mw-collapsed">
Click "Expand" to view.
Click "Expand" to view.

Latest revision as of 07:49, 19 March 2025

AMIBIOS, commonly stylized as AMI BIOS, is an IBM PC-compatible BIOS firmware. It was initially released by Access Methods Inc. in 1985 and later acquired and developed by American Megatrends (now AMI Inc.). It is also one of the first IBM PC-compatible BIOS firmware that were mass licensed for clone systems, released shortly after the competing PhoenixBIOS. Similar to that, it was also reverse engineered under a clean room solution to avoid infringement of IBM's copyright.

Its latest mainstream version, AMIBIOS 8, was phased out on most platforms released after 2010, in favor of modern UEFI-based firmware solutions (such as its successor AMI Aptio or the competing InsydeH2O). Despite this, it is still used on some industrial systems (such as the ones with the Vortex86 SoC) that are based on a legacy architecture. It is also commonly used on newer motherboards made for legacy platforms, especially LGA 775 and 1156 sockets.

Earlier instances of AMI Aptio contained an embedded version of AMIBIOS 8 as a component module for legacy boot (CSM) only mode (not to be confused with UEFI boot mode with CSM). However, since CSM was discontinued by Intel in 2020[1], this mode was removed along with its module. Although most newer instances still support UEFI boot mode with CSM support, this mode does not utilize the mentioned module.

Acquisition from Access Methods Inc.

Main page: American Megatrends

Access Methods Inc., a joint venture by Subromanian Shankar and Pat Sarma, released the first version of AMIBIOS in 1985.[2] Shortly after and due to legal issues, the owners found a new company with the funds raised by this joint venture. This venture was founded as Quintessential Consultants Inc. (QCI) and later renamed to American Megatrends Inc. (AMI) to keep the "AMIBIOS" acronym. The venture then acquired AMIBIOS from Access Methods next year.[3]

List of known versions

All versions before AMI Plus BIOS were initially released by Access Methods. Therefore, on most instances (ROMs) for these versions, the copyright strings mention "Access Methods Inc.". However, some of these versions were later continued to be developed by American Megatrends after the acquisition. Therefore, on these newer instances, the strings may sometimes mention "American Megatrends Inc." instead, despite not being initially released by them.

In most cases, the ROMs of all versions from AMIBIOS 2.x to AMIBIOS 6 and also AMIBIOS 7 (07.00.10) can be identified by the six-digit date shown in the identification string, which is displayed during the Power-On Self Test (POST). This is because these dates are actually fixed to the initial release date of the AMIBIOS version. However, occasionally, some OEMs modified these dates to reflect the ROM compile or release date instead, especially on early versions before AMI WinBIOS (AMIBIOS 4). The ROMs for AMIBIOS 07.00.xx (07.00.00) and AMIBIOS 8 also cannot be identified this way, as the date in their strings is actually fixed to the ROM compile date instead of the AMIBIOS version release date.

Please note that the following information may not be fully correct for versions released before AMI Hi-Flex BIOS, as their names had to be assumed due to lack of information and other references.

Version name First release date POST screen (if available) Known core dates Notes
AMIBIOS 1.x 1985 Not available The first version of AMIBIOS
AMIBIOS 2.x 1986 The name is assumed based on information from the unofficial MR BIOS website[4]
AMI Plus BIOS 1987 Name assumed based on information from the unofficial MR BIOS website[5]. Commonly nicknamed "AMI Pre-Color BIOS" due to its monochrome setup utility, which is the predecessor of Hi-Flex BIOS' setup utility (which is in color).
AMI Hi-Flex BIOS November 1990 Not to be confused with the Hi-Flex Setup Utility in AMIBIOS 6 and AMIBIOS 07.00.10. Commonly nicknamed "AMI Color BIOS" or "AMIBIOS Color" due to its colorful setup utility. Possibly also called AMIBIOS 3 internally, although unconfirmed.
AMI WinBIOS (AMIBIOS 4) December 1993 Not to be confused with the WinBIOS Setup Utility in AMIBIOS 6
AMIBIOS 5 October 1994 10/10/94
AMIBIOS 6 July 1995 07/15/95

07/15/97

07/15/99

Also known as AMIBIOS 97 (1997), AMIBIOS 98 (1998) and AMIBIOS 99 (1999)[6][7]
AMIBIOS 07.00.xx (07.00.00) 1999 Not used Officially named AMIBIOS V7.0[8], not to be confused with AMIBIOS 7 (07.00.10). Likely a pre-release version of AMIBIOS 8 (BigBIOS).
AMIBIOS 7 (07.00.10) April 2001 04/02/01 Also named AMIBIOS 07.00T. Possibly an update for AMIBIOS 6 for meeting the PC 2001 requirements.
AMIBIOS 8 October 2001 Not used Last commercial version of AMIBIOS. Codenamed "BigBIOS".
AMIBIOS 9 Unknown Not available. Not used Used in Microsoft Hyper-V. Possibly the name given to the BIOS emulation component for CSM/legacy only mode in AMI Aptio.

ROM identification string

The ROM identification string was first introduced with AMIBIOS 2.x and is often located at the bottom left of the POST screen. With this string, many useful details regarding the BIOS ROM can usually be gathered, such as the ROM size, chipset, motherboard manufacturer and sometimes even the AMIBIOS version. The string is formatted into sections with each containing different information regarding the ROM. The known codes for these sections are listed in the list of codes for BIOS strings (also available at the bottom of this page). The string format has been changed various times with some new releases of AMIBIOS.

AMIBIOS 2.x

MMMM-SSSSSS

  • MMMM: OEM identification code
  • SSSSSS: AMIBIOS version release date (occasionally modified to reflect the ROM compile date instead)

Example string: 1406-061286

This string is for an AMIBIOS 2.x version released on June 12, 1986 ("061286") for Flying Triumph Co. Ltd. ("1406").

AMI Plus BIOS

DCCC-MMMM-SSSSSS-KK (single digit CMOS setup type)

DDCCC-MMMM-SSSSSS-KK (two digit CMOS setup type)

  • D: CMOS setup type
    • This section can also be two characters long for "DE" if the ROM contains both built-in diagnostics and an extended setup.
  • CCC: Chipset type
  • MMMM: OEM identification code
  • SSSSSS: AMIBIOS version release date (occasionally modified to reflect the ROM compile date instead)
  • KK: Keyboard controller ID (with second character indicating the model).

Example string: D286-1277-043089-K0

This string is for an AMI Plus BIOS version released on April 30, 1986 ("043089") with built-in diagnostics ("D") for a machine with a discrete logic chipset for 80286 ("286") and a default/unknown keyboard controller (K"0") for Trangg Bow Co. ("1277").

AMI Hi-Flex BIOS and later versions

This format is also used by the earlier instances of AMI Aptio with the CSM module.

CR-VVVV-00MMMM-FFFFFFFF-SSSSSS-DDDDDDDD-Project-Y2KC-K

  • C: Processor architecture
  • R: ROM size
  • MMMM: OEM identification code
  • FFFFFFFF: BIOS feature identification
    • Usually "00101111" which is the default.
  • SSSSSS: ROM compile date (AMIBIOS 07.00.xx and AMIBIOS 8) or the AMIBIOS version release date (all other versions, excluding OEM modifications)
    • Note: Even on versions using the initial release date, this section was occasionally modified by the OEM to reflect the ROM release date instead.
  • DDDDDDDD: BIOS identifier (usually the chipset)
  • Project: Internal BIOS project ID
    • Only used on later revisions of AMIBIOS 6 and later versions.
  • Y2KC: Most likely an indicator for Year 2000 (Y2K) compatibility
  • K: Keyboard controller ID

Example string: 61-0530-001169-00101111-071595-440BX/ZX-1AAET006-R

This string is for a 05.30 version ("0530") 128 KB ("1")* size AMIBIOS 6 ROM ("071595", initial release date for AMIBIOS 6) for 686 architecture processors ("6") with Intel 440BX or ZX chipset ("440BX/ZX") and an AMIKEY '94 clone keyboard controller ("R") for project ID 1AAET006 of MSI ("1169").

* The BIOS ROM size is actually 256 KB in this specific case, the 128 KB size specified in the string is erroneous. This also proves that the string is not always fully accurate..

List of known codes for sections of the ROM identification string

Click "Expand" to view.

  1. ↑ https://www.intel.com/content/www/us/en/content-details/630266/removal-of-legacy-boot-support-for-intel-platforms-technical-advisory.html | Note: Although this document was published in 2023, it clearly mentions legacy boot being discontinued in 2020.
  2. ↑ https://twit.tv/shows/triangulation/episodes/226
  3. ↑ https://www.youtube.com/watch?v=5jYX3sL08Xs
  4. ↑ https://mrbios.com/techsupport/award/postcodes.htm | "AMI BIOS 2.2x" section
  5. ↑ https://mrbios.com/techsupport/award/postcodes.htm | "AMI Plus BIOS" section
  6. ↑ https://web.archive.org/web/19970623225759/http://www.amibios.com/amibios.html
  7. ↑ https://web.archive.org/web/19991012065711fw_/http://ami.com/amibios/bios.platforms.desktop.html
  8. ↑ https://web.archive.org/web/20000607010157fw_/http://www.ami.com/y2k_ami.html | "V.7.0" is listed as an AMIBIOS version, which must be 07.00.xx as 07.00.10 was not yet released at the time
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This page was last edited on 19 March 2025, at 07:49.