Removing password from Phoenix BIOS \ VOGONS

Removing password from Phoenix BIOS

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First post, by mpe

Posted on 2019-10-12, 22:56

mpe Offline

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I have a problem with my UM4981 AIO Rev 1.0 UM4981 AIO Rev 1.0 BIOS password. It 1994 486 board with Phoenix BIOS 4.03.

https://stason.org/TULARC/pc/motherboards/E/E … UM4981-AIO.html

The motherboard doesn't have any on-board battery. It only has a header for external 3V battery. Also there is no jumper for clearing password.

The board worked fine for some time, but then I changed configuration and it loaded default setup values for some reason (reported: Previous boot incomplete - Default configuration used). It doesn't boot with them (presumably as disk details are wrong).

From now on, my problem is that every-time I want enter setup it asks for 7 character password. I tried all different sorts of default passwords (PHOENIX, phoenix, CMOS, 1234567, ...). None of them seems to be working.

Once entering the password for the third time, it shows

SYSTEM DISABLED
(02F000)

It allows me to try the password again when I shorten the external battery header.

I did not set any password and was able to get to the Setup before this so this looks like a default password of some sort.

Any idea what the default password is or how to get rid of it? I thought 486-era boards should keep the password in CMOS and it should be easy to get rid of it. This one seems to be more sophisticated...

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Reply 1 of 5, by HanJammer

Posted on 2019-10-12, 23:35

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You may try reflashing the BIOS - it helped in case of my friend's motherboard with the same issue (and Phoenix BIOS - actually it might have been the sam board, definitely it had UMC chipset)...

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Reply 2 of 5, by Caluser2000

Posted on 2019-10-13, 00:34

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Try pulling the bios ans shorting all the pins at once on some ali foil.

There's a glitch in the matrix.
A founding member of the 286 appreciation society.
Apparently 32-bit is dead and nobody likes P4s.
Of course, as always, I'm open to correction...😉

Reply 3 of 5, by Horun

Posted on 2019-10-13, 01:40

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Hopefully that will work, according to the manual for UM4981 AIO R2.1 the CMOS and RTC are located inside the UMC8498F main chip. You could also try shorting pins 2 & 3 on the ext. battery connector (with computer off and ext. battery disconected)..

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Reply 4 of 5, by mpe

Posted on 2019-10-13, 09:24

mpe Offline

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Caluser2000 wrote:
Try pulling the bios ans shorting all the pins at once on some ali foil.

Will try that. But why would that work? Isn't it just an EEPROM chip?

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Reply 5 of 5, by konc

Posted on 2019-10-13, 09:50

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mpe wrote:
From now on, my problem is that every-time I want enter setup it asks for 7 character password. I tried all different sorts of default passwords (PHOENIX, phoenix, CMOS, 1234567, ...). None of them seems to be working.

I assume you tried hitting enter (blank password), right? Just stating the obvious as it has happened before

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