bjwil1991 wrote:

The main chipset is the 82C802 which I cannot find a MR-BIOS for this chipset or a one that's in 128BK in size.

The difference between OPTi 82C802G and 82C895 is the former supports more banks of RAM (8 banks vs 4 banks)

Ah. Can someone make the MR-BIOS to get implemented for the PB450 motherboard?

Here's the dumped BIOS image when I archived the chip a couple of months ago: https://drive.google.com/open?id=1P0uAcU2msT9 … yc_vI5QUEmjyb94

And for the 82C895 MR-BIOS: http://www.mediafire.com/file/49pbetqu7yyk4rl … R-BIOS_v202.zip <-- link from: How about a MR-BIOS ROM file repository?

Did the modifications on my Packard Bell PB450 motherboard (Packard Bell Pack-Mate 28 Plus), however, I didn't solder the battery holder very well and accidentally trimmed the legs off. Good news is, I bought two of them, same thing with the capacitors, fixed voltage regulators, and the VRM mounting kit.

Voltage regulator mod (cleaned the rest of the flux off, mostly after the picture was taken):

Battery holder (will fix):

Gallery: https://imgur.com/gallery/LBoMgt2

If you've ripped up a pin, you dont need to use the good battery holder, new one. You may cut a wire from a resistor from E-garbage and solder this to the holder. Empty the holes on board from tin, plug the new wire through the hole and solder VERY FAST so that it is not loosing connection on the first solder-point.

PS: I found this thread while googling for your MR-BIOS thing from vcfed forum 😀

bjwil1991 wrote:

Ah. Can someone make the MR-BIOS to get implemented for the PB450 motherboard?

IMHO the main problem is a module of videobios. How it can be extracted from Phoenix BIOS?
Are there tools to incorporate this module into MR-BIOS?
So first of all it's better to turn off the onboard graphics and test the system with MR-BIOS ROM and a discrete ISA graphic card.

I am already on this, see here:

http://www.vcfed.org/forum/showthread.php?666 … 2795#post542795

As you can read there, I already splitted on an old NCR video and system bios.
There are no tools for this. I have to identify and then use a hexeditor or a simple C program to assemble the pieces into a new image.
Yes, you're right about testing. First I want to build a 128k Image that just leaves the video bios stuff out - original BIOS. With this BIOS+ISA VGA the computer should start. If not - very hard to find out why.
If this image without Video BIOS works, I am going to replace the BIOS image in it with another one.

Luckily he has a EPROM/Flash writer, otherwise it would take days and postage-fee for every try.

Very interesting reading, including AMD/Cyrix CPU support, WB support, jumper settings, and other things.
https://web.archive.org/web/20000817071146/ht … bios/p4hs20.htm
It looks like the best bios available for this board.

Now we have to figure out how to get it out of that upgrade file p4hs20up.exe.
I tried to run it (btw, it only works when run from the diskette) but it gives me an error (see attached)
We need someone who can hack it and get it to run the flash routine.
Anyone with mad disassembling skillz here?

stecdose wrote:

If you've ripped up a pin, you dont need to use the good battery holder, new one. You may cut a wire from a resistor from E-garbage and solder this to the holder. Empty the holes on board from tin, plug the new wire through the hole and solder VERY FAST so that it is not loosing connection on the first solder-point.

PS: I found this thread while googling for your MR-BIOS thing from vcfed forum 😀

Idiot me forgot to put the jumper back on the battery pin header. I ended up swapping it with the spare and I'll keep the other one for a future board. Now I need to figure out why the L2 cache is causing my system to not load an operating system, but, it gets detected.

ahtoh wrote:

Very interesting reading, including AMD/Cyrix CPU support, WB support, jumper settings, and other things. https://web.archive.or […]
Show full quote

Very interesting reading, including AMD/Cyrix CPU support, WB support, jumper settings, and other things.
https://web.archive.org/web/20000817071146/ht … bios/p4hs20.htm
It looks like the best bios available for this board.

Now we have to figure out how to get it out of that upgrade file p4hs20up.exe.
I tried to run it (btw, it only works when run from the diskette) but it gives me an error (see attached)
We need someone who can hack it and get it to run the flash routine.
Anyone with mad disassembling skillz here?

Check here: Phoenix BIOS 4.03 v1.1a ISA Only (Packard Bell PB450M Motherboard) FCC ID: 450-459

Also, heed of warning: the BIOS would say the CMOS battery is "dead" for some reason (mine says that). Attempt to run the BIOS update diskette that you made and see if that helps clear it out.

bjwil1991 wrote:

Also, heed of warning: the BIOS would say the CMOS battery is "dead" for some reason (mine says that).

Did you try to clear CMOS? There's no special jumper for it on PB450 mainboard, but I suppose it could be done using J30 (open, no external battery)

I did try that as well, but, I didn't remove it for 5 seconds or power on the PC. Going to run the BIOS upgrade setup and see how that works. Also, thanks for making the BIOS ROM as well. It's also interesting to see the BIOS works with write-back cache, including the Pentium OverDrive processors, AMD or Cyrix, more RAM, bigger HDD support, and all of that good stuff that the PB BIOS doesn't offer. Also @ahtoh, how are the benchmarks between the WB and WT DX4-100 CPUs currently?

I posted the benchmark results a while ago, there is a 5% difference Re: Packard bell PB450 repair / mods / upgrade

Got the BIOS to work after running the upgrade. Thanks for the tip.

Great!
Do you think you can dump it with the programmer now?

Here it is as promised. Sorry for the delay. Was trying to figure out why my Creative Labs CD-ROM wasn't working properly and fixed it today.

ahtoh wrote:

Very interesting reading, including AMD/Cyrix CPU support, WB support, jumper settings, and other things.
https://web.archive.org/web/20000817071146/ht … bios/p4hs20.htm

Yes. For example, I didn't know there're such things:

Turbo speed switching is done with CTL-ALT-PLUS or CLT-ALT-MINUS with
both the original 4.03 or 4.05 BIOS and with the P4HS20 upgrade.
The motherboard does not support a hardware turbo speed switch.

bjwil1991 wrote:

Got the BIOS to work after running the upgrade. Thanks for the tip.

I've thought maybe "the option "Reset Configuration Data" could help, but now it doesn't matter.

Troubleshooting

Error message "Invalid System Configuration - Run Configuration Utility"

This message is from the BIOS and indicates that the ESCD (the area in the flash chip used to store Plug and Play information) has invalid or corrupted data and must be reset. This is done by setting the option "Reset Configuration Data" (on the Advanced menu in CMOS setup) to YES. This option will automatically be set back to NO after rebooting.

bjwil1991, ahtoh, did the new BIOS meet your expectations? I don't have PB450 system so I'm interested. 😀

I flashed it one of my boards, Media vision PAS16 works fine.
TLBMM hangs

also figured out why one of my boards do not work in the WB mode
Someone cut the Vcc pull up from the B13 pin

Ouch, man. I believe a dash of solder and a thin wire would fix that. Does your other board have that defect as well? Also, what is TLBMM?

Fixed that already.
TLBMM = The last byte memory manager
The bios works fine with WB chip, but the speed is a bit slower than 4.03 bios

Do you get the message about the EMM386 not loading?