I want to write down some lines about my experience with the mod BIOS for the ASUS A7V600-X board. But what makes the BIOS of this board special? Well, the postscreen says: "AWARD Medallion BIOS 6.0". By trying to look at BIOS modules and items with the tools: awbedit, cbrom and modbin, all three tools refuses to work with this BIOS. After some help from Antinomy and Tzk, we figured out, that we need a special cbrom version for this BIOS called "ACBROM" (A for ASUS?).
ACBROM recognizes this BIOS and this is how the modules look like:
What I see is, that all usuall modules in Award BIOSes are missing here (_EN_CODE, awardext, awardeyt ...). We also get new modules here like ENGLISHPOST, Other (1000:000), Group2+3+4.
After some research, I found the lables to the BIOS items in the Group2.rom module.
It seems like the "_EN_CODE" module for the labes is working here in a different way then in the usual Award BIOSes. The Group2 module beginns with a lot of CODE and about a half, the part of the labes begins:
We see some pointers to the BIOS pages : "Main", "Advanced", "Security", "Power", "Boot", "Server" and "Exit". I didn't check all pointers below the main menu, but these pointers seem not to contain all lables, just for some.
These lables got my attention:
Since the BIOS does not have any items for Dram Voltade or AGP Voltage, there should be some hidden items in the BIOS. I should take a look at the items.
The BIOS items are still located in the System module "MAINBIOS.BIN".
I marked the first item. You see the lable "303A"? It seems like the first lable in the Group2 module is for the first item in the system module. All items are grouped together as a single block of items. They weren't grouped in pages as Tzk found out in his post. Most items begins with a 00 or 01, so they should be all visible, but they aren't. Is there a lookup table with visible and non visible status? I could find anything. I also couldn't find any "$ml$" marker for BIOS pages as normal Award BIOSes do. No wonder the usual Award tools weren't able to read this BIOS. The whole "BIOS structure" is different.
I looked for the missing items for Dram- and AGP Voltage and found them in offset 1C4A7h and 1C48Eh.
For my first mod, i tried to replace two visible items with the items for Vdimm and Vagp. It didn't help, since they were still invisible. My second try was just to set a different Position marker in the strings (yellow marking in the screenshot above). I uses same position marker as the Vcore item (06 vs 1F)
That worked! The non visible items became visible! Now we are able to change the Dram Voltage in BIOS. The bad thing is, these Voltage changes doesn't work. So, these items are useless / non working.
My conclusion to this BIOS is, that there are invisible items and they weren't placed in the BIOS menu. By changing the position marker we are able to make this items visible. I will try to make more items visible and test them, but they aren't as important as Vdimm.