how to build 128KB bios image out of 256 kbyte bios image ?

maman · Thu May 20, 2004 5:34 am

I've successfully release "unneeded" stuff from my mainboard bios without loss of any important functionality. The "unneeded" stuff is the EPA logo, and a custom EPA procedure (procedure to display the EPA logo). The size of this new image is a bit less than 128Kbyte (compressed), but the original size of the bios image is 256Kbyte, hence cbrom or modbin will always emit 256Kbyte image out of this modified image. I intend to make it just 128 Kbyte image, and I have 128Kbyte flash chip to experiment with it. Is it possible at all to make a new 128 kbyte image? if it's possible then how to accomplish it?

Thu May 20, 2004 9:51 am

I've seen something like that in bp http://www.rom.by but never tried it.

sulbert · Mon May 31, 2004 1:00 pm

This feature was still under development in the last available version of BP.

maman · Mon May 31, 2004 5:30 pm

aha.., I see

. I've been "studying" BP for several weeks. I haven't got anytime testing it, but it's a very nice software. Thx, for the info. BP didn't mention about that feature in its readme file.

sulbert · Mon May 31, 2004 5:51 pm

Code: Select all

bp-4_51 /h

says:

Code: Select all

/u - "ultrapack": packs 2Mbit/4Mbit-BIOS to 1Mbit (N/A - in development)

As far as I have understood the thing, the main idea behind this are better (more effective) compression routines.

maman · Sat Jun 12, 2004 5:52 am

a better compression routine

. AFAIK, bios is LZH compressed, so it must still a variant of the LZH. This BP is really interesting

.

sulbert · Mon Jun 14, 2004 9:55 am

maman wrote:so it must still a variant of the LZH

Why? The uncompress routine is also replaceable, isn't it?

maman · Tue Jun 15, 2004 1:14 pm

yup right, I'm just fool enough right now, not being able to implement a better compression routine in assembly language other than variant of the "moving window" such as LZH

to meet the small space requirement in the BIOS.

apple_rom · Sun Jul 18, 2004 4:23 pm

Is it possible at all to make a new 128 kbyte image?

It`s possible. I even once upon a time successfully this do. But this anymore was required, therefore so and not realize this possibility in its program (though on 80% has written).

if it's possible then how to accomplish it

1. remove ALL not-used files. (as a rule, stays only "original.tmp" and "awardext.rom").
2. place original.tmp in begin of 128k-bios.
3. awardext.rom place in the end of him and some not-used places (u can divide by some parts).
4. rewrite unpacking-procedure in boorblock - after unpacking "original.tmp" so to first was going to from pieces your awardext.rom on original.tmp-place, and after that uncompress him...

Some comments - you not will have no DMI/ESCD, and must to remove CRC-checking...

maman · Mon Jul 19, 2004 5:20 pm

apple_rom wrote: 1. remove ALL not-used files. (as a rule, stays only "original.tmp" and "awardext.rom").
2. place original.tmp in begin of 128k-bios.
3. awardext.rom place in the end of him and some not-used places (u can divide by some parts).

I have done this

. The another two haven't yet. I'll try later. Thx