MechKnight wrote on 2021-05-16, 16:14:

So I've got a Gateway2000 4sx-33 that I love dearly, being my only sort of working retro pc, but the bios infuriates me. it's a phoenixbios a486 v1 that not only has the 504 mb limit needing a ddo, but refuses to even boot without a charged cmos battery and something on the board keeps draining mine in a few days. I've cut myself on the case enough times to want to open it as little as possible and that leads me to my question. If I were able to pinpoint the bios chip on the motherboard, could I simply replace/reflash it with a bios that sucks less or are 486 era bios's linked somehow with the exact hardware on the board? Everything I've searched for on google got modern pc's where flashing a bios is super easy but this dates from like '92. Thanks for reading, and more generally, thanks to vogon's for this entire site! It's helped me a lot already

BIOSes on boards of that era and newer are not typically interchangeable (unless, for example, in your case if Gateway used a board from a contract manufacturer that also happened to sell the board separately and provided BIOS updates for it).

BIOS chips of that era usually needed to be erased using UV light and flashed externally (using a an EPROM programmer). Electrically re-programmable BIOS chips that can be flashed in the motherboard itself only started becoming common on later generation hardware . EDIT : At least some motherboards in Gateway 2000 486 machine seem to be easily flashable . Yours may be one of those or not.

What type of battery does the board use ?

EDIT : If you can ID your board type, you might find some useful info here : https://web.archive.org/web/20001109053200/ht … ard/index.shtml

Thankfully it uses cr2032's, which I found surprising considering its age, but it's way better then a barrel battery. I don't mind buying an eprom programmer, but I'd rather not waste $60 if the idea isn't feasible. I don't know if it's the chipset or an actual designation for the motherboard, but when I first got the computer, I found a page on stason.org with the right layout and jumper settings for everything and according to that, it's an intel 486 classic R.

Thank you .

Based on the info provided .

Your board is one of these :
https://web.archive.org/web/20001109052700/ht … ard/i4/i4.shtml
Even the official Gateway BIOS for this limited to 528MB

However, there was a third party BIOS update available at a cost :
https://web.archive.org/web/20001003032421/ht … bios/i4hs10.htm

Currently, other than using a DDO , the most practical option is to install a card with the XTIDE BIOS . See here http://www.xtideuniversalbios.org/

As for the CR2032 battery going flat in days, are you using brand-name store bought batteries, if you don't mind me asking ?

"Maybe a stupid question about 486 bios"
As one of my teachers said, "there are no stupid questions, just stupid answers" .

Some systems require a CMOS battery in order to work, because they directly read the BIOS settings from the little RAM that's inside the Real-Time Clock.
Problem is, without the CMOS battery, some of these clocks get no power at all in worst case and don't function.

And without that RAM access, these systems do not have default values at hand.
That's because they do work differently..

Some other BIOSes of the era keep a seccond copy of the settings in the computer's RAM after a soft-reset.

The reason why the date/time retrieval still works is simple :

There are two clocks in a PC.
a) The Real-Time Clock (RTC)
b) The softeare-based MS-DOS clock - $clock

Normally, the MS-DOS clock retrieves its time from the RTC during boot.
But it can also work without it.
That's why DOS works on XTs without a clock card, too.

Sorry for the huge delay, work picked up and I didnt have time to work on this. I bought a xtide card manufactured by blue lava systems, only it doesnt detect the card at all! Plugging my CF adapter into the xtide card or into the multi io card I've been using makes no change. As for the batteries, Duracell 2032s bought at costco with a best before date of 2030 so they're good quality. I might just give up on this for now and try and get my grandfathers old amd k5 working. At least with that I dont have to open a case and risk giving a blood sacrifice, since I don't even have a baby at case right now ha!

Edit: Well, I think I know part of the problem, at least with the xtide not detecting the card. I was testing it again earlier hoping something had magically fixed itself, and a trace went up in a puff of smoke on my cf-ide adapter! Who knew no name chinese electronics might not be manufactured to the highest standards? Looks like I'm buying a new adapter.