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2017-04-26
How to flash a PC FlashBIOS... :)
2000-08-06

Usually, when you want to update a PC BIOS, you will use a flash utility like AwardFlash (awdflash.exe). This small program accesses directly the FlashROM which contains the computer's BIOS.
Some weeks ago, my brother wanted to upgrade his PC (an older PII-233) with a Celeron333 CPU. Well, what can we expect by "compatible" computers: it didn't work... after a look at the motherboard's vendors homepage we knew, that the BIOS was rather old and newer versions should support the Celeron CPU, too.
After downloading the update and the flash-utility, the try to update the BIOS failed. The tool said, that the 128kB update file was too small - no wonder: the computer had a 256kB FlashROM built in...
After contacting the support, they told us, that it should work; they sent us an other flash-tool but this didn't work either...
Well... what to do now? Buy a newer board with those >500MHz CPUs noone really needs - and put the old stuff into the trash? No. There must have been be an other solution: I would burn the Flash myself by hand! :)

Original BIOS FlashROM Here is a picture of the original FlashROM (an Atmel 29C020). I downloaded the datasheets for this chip and decided not to program this chip because of its unusual programming algorithm. I also wanted to have a true (working) backup.

My favourite FlashROMs are from AMD - they are really nice to handle because they have a smart programming algorithm. And the biggest advantage: I already had some of those chips here... ;)
As I had only 29F040-chips in a PLCC-package, I had to solder a small adaptor to the 32Pin DIL-package of the original FlashROM.
This picture shows the result of my work - a PLCC-socket with flying vero-wire wires soldered to a DIL-socket. Well, not the nicest version (no PCB...), but for one single chip in my opinion the best solution. FlashROM replacement

Now you surely ask yourself: "how does he want to program the chip?". A good question - as I do not have a professional programming device (they are rather expensive) I did it my own way. I used a small and very very old Microcontroller (8052AH-BASIC) from intel (yes, intel-crap, I know...) which provides a full BASIC-interpreter in its ROM. It is very slow but it provides enough IOs to connect a FlashROM to it. As it only has 64kB address-space, I had to add some more address-lines by using some of its other IOs. The programming software I programmed already some time ago and it really works nice.
The microcontroller-board was connected over a serial connection to my Amiga 3000 where I use Term4.8 to have terminal-access. The data-upload was managed by my programming software on the microcontroller and a small ARexx-script which feed Term with the data it had to send to the board.

Programming the FlashROM... Here you can see the mentioned microcontroller board with the connected FlashROM. Looks crazy? - No thats normal! ;)

Perhaps you now want to know what data I programmed in the Flash - the file is 128kB and the chip 256kB... Well... I joined the first 128kB of the old chip contents together with the BIOS update. This results in a 256kB file - I didn't know if it would work, but it was worth a try... :)
After programming the chip, I inserted the whole thing into my brother's PC.
It worked! :) - Now everything works and he can use his new Celeron-CPU...


Here is a picture how the whole thing looks like:
Mounted wired FlashROM


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