AWARD BIOS - extracting and rebuilding ACPI tables from module BIN

[ashm]

Hi, first time posting, I hope someone here can help.

BLUF: Please can anyone advise me on how to extract the "ACPITBL.BIN" from a Phoenix/AWARD v6.00PG BIOS into the various AML and ACPI data tables that it contains, and how to reverse the process to compile the ACPI tables into a BIN module that can then be inserted into a BIOS?


Long version:

I have an Intel GM45/ICH9M-E based Jetway NF93R-LF motherboard salvaged from an old network appliance, which I have abused greatly beyond the intent of its designers and which is now running various services on my home network.  It's quite a neat little board, it fits nicely in a very small case and I intend to push it as long as I can rather than replace it if possible.

This board originally came with some anaemic Celeron CPU which I have since upgraded to a slightly less anaemic core 2 extreme (quad) QX9300, which sort of half works so long as I disable the speedstep / cpufreq driver in linux.

Looking at the ACPI SSDT configuration, the BIOS was clearly never intended to run with speedstep active as the _PSS list is gibberish (eg. frequencies at 17.6GHz, nonsense register values etc.).  As a result, with speedstep active the CPU sits locked to 1600MHz and won't scale over this as there are no valid speedstep profiles in the _PSS list.  With cpufreq disabled the cpu runs at spec of 2533MHz when unloaded, but cores drop to 1600MHz when loaded which is a bit counterproductive from a performance standpoint.

I have reverse engineered the DSDT and the 6 SSDTs, and with some detective work, educated guessing and experimentation I have built a valid table of frequency/voltage modes that the CPU will correctly run at.  I can now enable and control speedstep manually by writing the magic values to the relevant CPU model specific registers.  I can also override the BIOS ACPI tables by manually overwriting the DSDT and SSDTs from the OS kernel at boot time, which then works perfectly, though this is a bit clunky to do in linux.

Now that I know for a fact that the board itself is fully capable of running C2D/C2Q CPUs with speedstep, I want to roll my corrected ACPI tables back into the BIOS (which is otherwise fine) and have a fully speedstep-enabled (and properly performing) board with no need for boot-time overrides.

It seems that the ACPI tables live in a BIOS module called "ACPITBL.BIN".  I can extract the file from the BIOS image using CBROM, and I can see that it seems to contain the relevant tables, but I can also see that it seems to be some sort of compressed archive with a header that I don't recognise.  I can't figure out what sort of archive they are compressed into and therefore how to decompress or recompress them.  It doesn't seem to be a simple concatenation (as it has a ~50% compression ratio), nor LHA / LZH which I believe is commonly used for BIOS modules, as it's missing the correct header.  I'm sure the answer must be quite simple, but several evenings of reading have not yielded the answer so can anyone here point me in the right direction?

The first few lines of "ACPITBL.BIN" are shown in the attached image.

Any help much appreciated, thanks.