BIOS patches

ASUS Pentium II / Pentium III mainboard patches

In this section, you will find modifications of BIOS images for various ASUS mainboards of the Pentium II and Pentium III era, i.e. mainboards with a Slot 1 (SC242) or socket 370 processor connector. The images have been altered to provide small fixes or extend support for additional processors. (Refer to the list of changes below.)

Warning: I do not own the vast majority of the mainboard models listed below. Only some of the modifications have been tested extensively. Some are even purely hypothetical and have not been tested at all.

Flashing these modified BIOS images might cause your system to fail POST. Make sure you know how to perform a crisis recovery (e.g. by means of an external programmer) before using any of these images.

Changes for all mainboards:

• POST screen and system summary screen show correct processor brand names for processors up to Pentium III-S.
• POST screen and system summary screen show correct normalized frequencies for multipliers 12.5x through 16.0x at standard FSB speeds.
• POST screen and system summary screen show correct frequency suffixes (A, E, B, EB) according to Intel datasheets.
• Processor microcodes have been updated.
• Experimental support for Via C3/Cyrix III processors has been added or expanded, including the ability to enable or disable the processor's L2 cache.
• In Setup Utility, an "Enable" option for Symbios SCSI BIOS/Onboard SCSI BIOS/Onboard AHA BIOS (depending on model) has been added. This option forces loading the Symbios ROM module even if no matching adapter is present.

Changes for mainboards with JumperFree capability:

• Lower core voltages for undervolting have been unlocked.
• Display of multiplier 2.0x for processors with Klamath core has been fixed.
• The "Advanced" tab of the BIOS Setup Utility supports multipliers 12.5x through 16.0x, including display of suggested processor frequencies for standard FSB speeds.

Changes for mainboards with a hardware monitoring IC:

• Voltage ranges for various processor types have been added to suppress Hardware Monitor errors during POST.
• Hardware Monitor can monitor slow-spinning fans (down to ca. 700 RPM, warnings at ca. 900 RPM).
• Hardware Monitor errors and erroneous readings ("-6.14V", "0.1V" or similar) when using modern PSUs without a -5 V rail are suppressed.

Changes for mainboards with a Slot 1 (SC242) processor socket:

• POST has been fixed for Pentium Pro processors. (There might still be shutdown problems for ACPI-capable mainboards.)

Changes for mainboards with an Award Medallion 6.0 BIOS:

• The SMBIOS fields for "Processor Version" and "Processor Family" are populated with more meaningful values.
• The boot menu hotkey has been changed from Escape to F10, and a matching message has been added to the POST screen.

Downloads

Mainboard	BIOS version	Download	Notes and comments
CUBX	1008 Beta 004	1008cu004_20240219.zip	The CMD Ultra66 ROM has been updated to version 1.9.16.
CUBX-E CUBX-L	1008 Beta 004	1008cul004_20240219.zip	The Promise Ultra100 ROM has been updated to version 2.20.0.14.
CUV4X	1010 Beta 003	1010-003_20240620.zip
CUV4X-CME	1002 Beta 002	1002cme002_20240219.zip
CUV4X-D	1016	cuvd1016_20240219.zip
CUV4X-DLS	1016	vdls1016_20240219.zip
CUV4X-E (without onboard audio)	1005 Beta 005	1005-005_20240620.zip
CUV4X-E (with onboard audio)	1006 Beta 005	1006-005_20240620.zip
CUV4X-M	1008 Beta 003	1008m003_20240219.zip
P2-99	1013 Beta 005	zxnh1135_20230728.zip
P2B (with hardware monitor)	1014 Beta 003	1014-003_20230728.zip
P2B (without hardware monitor)	1014 Beta 003	1014nh03_20230728.zip
P2B-B	1014 Beta 003	1014b003_20230905.zip
P2B-D	1014 Beta 003	1014d003_20230728.zip
P2B-DS	1014 Beta 003	1014ds003_20230728.zip
P2B-F (with hardware monitor)	1014 Beta 003	1014f003_20230728.zip
P2B-F (without hardware monitor)	1014 Beta 003	1014fn_20230823.zip
P2B-N (with ATI 3D Rage IIC)	1014 Beta 003	1014niic03_20230728.zip
P2B-N (with ATI 3D Rage Pro)	1014 Beta 003	1014npro03_20230728.zip
P2B-S	1014 Beta 003	1014s003_20230803.1.zip
P2B-VM (without onboard audio)	1014 Beta 003	1014vm003_20230905.zip
P2L97 (with hardware monitor)	1010 Beta 004	lx10104_20230728.zip	Due to a ROM size of only 128 KiB, this model does not have a Symbios option ROM at all. The hardware monitoring IC on this model does not support programming the third fan input. The lower bound of the chassis fan monitor is thus hardwired to ca. 2600 RPM.
P2L97 (without hardware monitor)	1010 Beta 004	lxm10104_20230728.zip	Due to a ROM size of only 128 KiB, this model does not have a Symbios option ROM at all.
P2L97A	1010 Beta 004	lxa10104_20230728.zip
P2L97-S	1010 Beta 004	lxs10104_20230728.zip	The hardware monitoring IC on this model does not support programming the third fan input. The lower bound of the chassis fan monitor is thus hardwired to ca. 2600 RPM.
P2Z	1013 Beta 005	zx9i1135_20230728.zip
P3B-1394	2004 Beta 001	2004001_20230905.zip
P3B-F	1008 Beta 004	p3bf1084_20240219.zip
P3C-E (with onboard/non-onboard audio)	1025 Beta 002	1025e_20240219.zip
P3C-E (with software AC97 codec)	1025 Beta 002	1025e_swa_20240219.zip
P3V133	1003 Beta 002	pv133132_20240219.zip
P3V4X	1006 Beta 004	pv4x1064_20240219.zip
TUV4X	1006 Beta 002	1006-002_20240620.zip

Other patches

Mainboard	BIOS version	Download	Notes and comments
ASUS P5E3 Pro	0505	P5E3-PRO-ASUS-0505_20201212.zip	The Intel Rapid Storage Technology option ROM has been updated to version 10.5.1.1070 to support RAID configurations with drives larger than 2 TiB. Processor microcodes have been updated.
Gigabyte GA‑BX2000	F9	motherboard_bios_ga-bx2000_f9_20231017.zip	The weirdly colored DualBIOS logo has been replaced by a custom repainted logo. Processor microcodes have been updated.
Gigabyte GA‑BX2000+	FD	motherboard_bios_ga‑bx2000plus_fd_20230801.zip	The weirdly colored DualBIOS logo has been replaced by a custom repainted logo. Processor microcodes have been updated.