brad162 wrote on 2026-10-07, 09:51:

I got excited finding this but dreaded enough the M4HS50 is not in there, but 45 is. […]
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RyanH-Nostalgia wrote on 2026-01-22, 18:16:

hyoenmadan wrote on 2026-01-03, 05:47:

Micro Firmware upgrade BIOSes aren't even complete ROM images, but only the upgraded modules, compressed and padded with certain patters known to their upgrade program (like many Phoenix and Intel BIOSes), so it can flash them in their correct rom blocks. Generally them don't even come with the BootBlock, and ofc the firmware Serial ID is "tattooed" in a block which also is never present in the upgrade image.

If you want to modify a MF BIOS, your best bet would be first upgrade the firmware with the supplied files and install program, dump it with an EEPROM programmer, modify the updated image, and then reflash it using the hardware programmer again.

PD: Take in count MF upgrade diskettes can only update MF ROM chips. MF "kits" consisted in a physical EEPROM chip to install in the board preflashed with the full version of the MF BIOS specific to your board, and a separate diskette with some diagnostic program, and in some cases, an upgrade program to flash the supplied chip to the latest version available to your board (most probably to avoid having to reflash the whole chip stock in case there were last time corrections to the supplied chip). No known MF software disks can change the original manufacturer existing BIOS to the MF supplied version. You need their supplied chip to be present (or a full EEPROM dump from someone else, to flash in a blank chip with a hardware programmer).

The Micro Firmware BIOS upgrades that you are thinking of are the Hardware Replacement ROM Chips that were meant to replace the original non-programmable EPROM Chips in a System. From what I have researched, there were a total of 5, the other BIOS Upgrades that Micro Firmware made came on just a floppy disk as the BIOSes for those systems can be reprogrammed. For example, with my Gateway 2000 4DX2-66V (Which has a Micronics Motherboard, Part Number: 09-00144) I was able to try out other BIOSes that did not quite work and was also able to use a BIOS Recovery Diskette that I made as well using a Jumper setting on the motherboard. As far as I know, there are a total of 23 BIOS Upgrades that came on just a Diskette with their own serial numbers. Another example is that YouTube User retrobits has a Gateway 2000 486 with a different motherboard than what mine has (Micronics Motherboard Part Number: 09-00189) and he has a Micro Firmware BIOS Upgrade on Just the Diskette and he did not need to replace the BIOS ROM Chip in his system as it can be reprogrammed and he has used the Micro Firmware BIOS Upgrade with his and the Micro Firmware BIOS Upgrade for his is M4HS45GP and the one I am looking for is M4GS25 or a way to Modify an UPDATE-ONLY Version into a NON-UPDATE-ONLY Version using a HEX Editor or a similar program without corrupting the INSTALL.EXE file. I hope I was able explain this correctly. I also made this custom Chart of every Micro Firmware BIOS Upgrade that was made and what I was able to find that way everyone can get a full understanding of these Micro Firmware BIOS Upgrades.

I got excited finding this but dreaded enough the M4HS50 is not in there, but 45 is.

This old 4SX-33 (upgraded to a 100MHz Overdrive) has terrible BIOS with the 528MB limit on the HDD.

I'd extract the bios and edit it, but i'm not good at editing bios - nor would I know how to fix that... One day this bios *might* pop up... as this board is even buggy with XT-IDE bios too.

if your motherboard is MIC471 chipset based i think you can try to use MR.BIOS for SIS 460/461 motherboards

Babasha wrote on 2026-10-07, 12:02:

brad162 wrote on 2026-10-07, 09:51:

I got excited finding this but dreaded enough the M4HS50 is not in there, but 45 is. […]
Show full quote

RyanH-Nostalgia wrote on 2026-01-22, 18:16:

The Micro Firmware BIOS upgrades that you are thinking of are the Hardware Replacement ROM Chips that were meant to replace the original non-programmable EPROM Chips in a System. From what I have researched, there were a total of 5, the other BIOS Upgrades that Micro Firmware made came on just a floppy disk as the BIOSes for those systems can be reprogrammed. For example, with my Gateway 2000 4DX2-66V (Which has a Micronics Motherboard, Part Number: 09-00144) I was able to try out other BIOSes that did not quite work and was also able to use a BIOS Recovery Diskette that I made as well using a Jumper setting on the motherboard. As far as I know, there are a total of 23 BIOS Upgrades that came on just a Diskette with their own serial numbers. Another example is that YouTube User retrobits has a Gateway 2000 486 with a different motherboard than what mine has (Micronics Motherboard Part Number: 09-00189) and he has a Micro Firmware BIOS Upgrade on Just the Diskette and he did not need to replace the BIOS ROM Chip in his system as it can be reprogrammed and he has used the Micro Firmware BIOS Upgrade with his and the Micro Firmware BIOS Upgrade for his is M4HS45GP and the one I am looking for is M4GS25 or a way to Modify an UPDATE-ONLY Version into a NON-UPDATE-ONLY Version using a HEX Editor or a similar program without corrupting the INSTALL.EXE file. I hope I was able explain this correctly. I also made this custom Chart of every Micro Firmware BIOS Upgrade that was made and what I was able to find that way everyone can get a full understanding of these Micro Firmware BIOS Upgrades.

I got excited finding this but dreaded enough the M4HS50 is not in there, but 45 is.

This old 4SX-33 (upgraded to a 100MHz Overdrive) has terrible BIOS with the 528MB limit on the HDD.

I'd extract the bios and edit it, but i'm not good at editing bios - nor would I know how to fix that... One day this bios *might* pop up... as this board is even buggy with XT-IDE bios too.

if your motherboard is MIC471 chipset based i think you can try to use MR.BIOS for SIS 460/461 motherboards

It's a Gateway 2000 4SX-33 with the Anigma board, it has an Opti 82C495B chipset.

Need help identifying Gateway 4SX-33 motherboard and jumper settings

The one mentioned here.. I'd be fine with this bios, but it will *not* boot ANY CF card, even with an overlay. I assume this bios is just fickle with HDD access, and the 1GB Seagate I've got in here is finally starting to die.

brad162 wrote on 2026-10-13, 22:25:

It's a Gateway 2000 4SX-33 with the Anigma board, it has an Opti 82C495B chipset. […]
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Babasha wrote on 2026-10-07, 12:02:

brad162 wrote on 2026-10-07, 09:51:

I got excited finding this but dreaded enough the M4HS50 is not in there, but 45 is.

This old 4SX-33 (upgraded to a 100MHz Overdrive) has terrible BIOS with the 528MB limit on the HDD.

I'd extract the bios and edit it, but i'm not good at editing bios - nor would I know how to fix that... One day this bios *might* pop up... as this board is even buggy with XT-IDE bios too.

if your motherboard is MIC471 chipset based i think you can try to use MR.BIOS for SIS 460/461 motherboards

It's a Gateway 2000 4SX-33 with the Anigma board, it has an Opti 82C495B chipset.

Need help identifying Gateway 4SX-33 motherboard and jumper settings

The one mentioned here.. I'd be fine with this bios, but it will *not* boot ANY CF card, even with an overlay. I assume this bios is just fickle with HDD access, and the 1GB Seagate I've got in here is finally starting to die.

I can try to prepare MR.BIOS for your board but i need full dump of your current BIOS and hi-res photo of both sides with readable text on all chips of your motherboard.