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how to build 128KB bios image out of 256 kbyte bios image ?
Posted: Thu May 20, 2004 5:34 am
by maman
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?
Posted: Thu May 20, 2004 9:51 am
by Rainbow
I've seen something like that in bp
http://www.rom.by but never tried it.
Posted: Mon May 31, 2004 1:00 pm
by sulbert
This feature was still under development in the last available version of BP.
Posted: Mon May 31, 2004 5:30 pm
by maman
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.
Posted: Mon May 31, 2004 5:51 pm
by sulbert
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.
Posted: Sat Jun 12, 2004 5:52 am
by maman
a better compression routine
. AFAIK, bios is LZH compressed, so it must still a variant of the LZH. This BP is really interesting
.
Posted: Mon Jun 14, 2004 9:55 am
by sulbert
maman wrote:so it must still a variant of the LZH
Why? The uncompress routine is also replaceable, isn't it?
Posted: Tue Jun 15, 2004 1:14 pm
by maman
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.
Posted: Sun Jul 18, 2004 4:23 pm
by apple_rom
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...
Posted: Mon Jul 19, 2004 5:20 pm
by maman
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