Hi,

AFAIK, the socket itself has nothing to do with HDD size detection, it is most likely a BIOS issue, or maybe a chipset limitation.

When using this motherboard be aware that the earliest Pentiums had a floating point calculation bug, but if you only use the board for purely gaming purposes then this doesn't matter. 😀

EDIT:
Can you post a screenshot of the HDD configuration in the BIOS? It should be inside the "STANDARD CMOS SETUP" menu.

As the hang is in the middle of detecting drives, in the interest in troubleshooting, why don't you use xtidecfg to set the number of controllers to 1 (to get rid of the secondary controller), then go into primary IDE controller->slave drive->disable detection [Yes] to get rid of the "slave" drive.

It should be printing "not found" there, obviously.

Omarkoman wrote on 2026-05-09, 23:23:

So what options do I have to get a 8GB drive recognised correctly in this system ? If I have to, I can live with a 2GB max drive size which is plenty for DOS (this will be a purely DOS machine, maybe win 3.11) but still, I cant help it and want to try figure it out.

Depending on the exact Award BIOS and what bugs it does or doesn't have, there were some that properly support drives up to the 8.4GB limit, but that have a purely cosmetic bug where they miscalculate the displayed size. If you're lucky, it's that.

MagefromAntares wrote on 2026-05-10, 00:13:

Can you post a screenshot of the HDD configuration in the BIOS? It should be inside the "STANDARD CMOS SETUP" menu.

here is a pic of a HDD and how its detected in BIOS:

https://i.postimg.cc/cZ1HXGQC/IMG-3968.jpg

https://i.postimg.cc/yB6dvCFd/IMG-3969.jpg

Omarkoman wrote on 2026-05-10, 01:50:

here is a pic of a HDD and how its detected in BIOS: […]
Show full quote

MagefromAntares wrote on 2026-05-10, 00:13:

Can you post a screenshot of the HDD configuration in the BIOS? It should be inside the "STANDARD CMOS SETUP" menu.

here is a pic of a HDD and how its detected in BIOS:

https://i.postimg.cc/cZ1HXGQC/IMG-3968.jpg

https://i.postimg.cc/yB6dvCFd/IMG-3969.jpg

This is the first HDD I assume, its addressing mode is set to NORMAL in the BIOS, but to have more than 2.1 GB accessible that needs to be set to either LARGE or LBA, the HDD has LBA printed on it, so I think that should be the correct choice.

I believe you are lucky and that 2GB is just cosmetic. 16383x16x65535 is correct for the 8.4GB limit. What happens if you proceed to fdisk and set up your OS anyway?

See Chkcpu's description here: Re: Diy modding support for k6+And 120gb hard drives into bios roms

Doesn’t seem like the usual bugs where the bios config program or int13h have trouble with too many cylinders. Or the phoenix 2gb bug where the bios config tool crashes if you go over a capacity > 32bit signed int.

Looks like XTide universal bios is crashing.

Maybe there is something in your system that’s not completely compatible with XTide.

Or maybe something is wrong with your rom or the card where you mounted the rom.

I have multiple NICs with XT-IDE ROM on them , I tried 3, they all behave same.

I will try to setup the HDD (the mechanical one) as BIOS detects, select LBA and see what DOS fdisk can see, I'll report back shortly. I'll also download the xtidecnf utility, I havent used it before but lets see.

thanks for all the questions / suggestions so far !

Omarkoman wrote on 2026-05-10, 02:10:

I will try to setup the HDD (the mechanical one) as BIOS detects, select LBA and see what DOS fdisk can see, I'll report back shortly.

Don't forget the pre Win95B DOS fdisk will apply its own 2GB per partition limit because of FAT16, and that isn't an indication of any Award bug.

I am using dos 6.22 and normally partition the 8gb drive into 4x2gb partitions as thats max 6.22 dos can do and i dont like to use higher versions / freedos.

And yes, you were correct! Its only cosmetic in bios! The drive reports full size in fdisk!!! Wow, so weird!

Nice. The thing is, other than for the GUI, the BIOS only cares about maximum cylinder/head/sector, and doesn't care about how many megabytes the drive is.

I haven't looked at the actual bug. But, if you multiply 16383*16, truncate that result to 16 bits (as if looking at ax only instead of dx:ax), and multiply by 63, and then divide that 32 bit result by 2048 to convert from sectors to megabytes, you indeed get 2015.

I tried few different ISA controllers (eg classic prime 2c mkiii) and 3 different VLB controllers. VLB controllers.....
do you have vlb ide controller's bios dumpped?if you have could you share with me?

Sorry no I dont have any of the BIOS dumped.

jakethompson1 wrote on 2026-05-10, 02:28:

I haven't looked at the actual bug. But, if you multiply 16383*16, truncate that result to 16 bits (as if looking at ax only instead of dx:ax), and multiply by 63, and then divide that 32 bit result by 2048 to convert from sectors to megabytes, you indeed get 2015.

Hi jakethompson1,

Your reasoning and calculations are spot on. This is exactly what happens with this 2GB display limit bug.

The routine that calculates the drive size loads the Cylinders count in AX and the number of heads in CL. The CH register is zeroed so that a MUL CX instruction puts the Cyl*Heads product in DX:AX.
Then the CL register is loaded with the Sectors/Track count and another MUL CX instruction is executed, multiplying AX by CX. This is where the 16-bit truncation happens because the value in DX is ignored.
Now CX is loaded with 0x800 (2048), followed by a DIV CX instruction. This will correctly divide DX:AX by CX, producing the drive size in MB in AX.

I found this routine in pre-translating Award BIOSes as well, where it worked fine because of the 504MB limit then. But by truncating the 32-bit result of the first multiplication to 16-bit, this logic is only good up to CHS values of 4095x16x63 (2015MB).

Note that due to the values used, the MB value calculated by the above routine is the binary 1024x1024 MiB type, the same a shown by FDISK.
Around that 1994/1995 time, BIOS vendors started to use the decimal 1000x1000 MB value for drive size indication, and a slightly altered routine was used. But curiously, this altered BIOS routine by Award still had the same 16-bit truncation.
Only by the end of 1995, Award properly fixed this bug.

In my DIY BIOS modding guide, I show a fix for both cases. These fixes work by altering the multiplication sequence, so the truncation will not occur.
I will send the OP a fixed PB5500c BIOS with proper drive size indications up to 8GB.

Cheers, Jan

Thank you Jan !!!!!!!!!!!!!

Hi Omarkoman,

The patched MiTAC/Trigon PWA-PB5500C Rev 1.02 BIOS is ready and here is a zipped copy:

The filename of this patch J.1 BIOS is 5500C_J1.BIN, and in the zip-file I’ve added a PATCH.TXT file that lists the changes I’ve made.

Apart from fixing the 2GB HDD size display limit bug, I found a lot of hidden BIOS Setup options, specifically for L2 cache and DRAM timings.
I even found a completely hidden PCI CONFIGURATION SETUP menu!
I’ve enabled all these hidden options, so you now have a lot more possibilities to tweak the chipset settings. 😀

Enjoy your new BIOS, and I love to hear how it works for you.

Cheers, Jan

amazing, thank you so much !

I will give it a whirl and report back !