Prev: Call for papers (Deadline Extended): HPCS-10, USA, July 2010
Next: Multi-core lag for Left 4 Dead 1 and 2 and Quake 4 on AMD X2 3800+ processor... why ?
From: Skybuck Flying on 27 Mar 2010 01:59
I have tried and done the following things:

1. Downloaded the bios rom from bios chip to floppy disk.
(Special AFUDOS bootdisk needed) (It's kinda strange afudos didn't want to
run with ms-dos 6.22 bootdisk, so it needs it's own special dos ?)
(Fortunately I already had all the necessary disks from the past
experimention with bioses ;) :))

2. Transferred the bios rom image from floppy disk to harddrive to my
information folder for future archiving. (I make backups of my information
folder regularly, like each year or so... this will be handy if I want to
inspect the suspicious bios in the future in case current software is
inadequete).

3. Downloaded special AMITOOLS to investigate American Megatrends Inc.
bioses. (I guess these tools are not available by official channels, and
must be downloaded from pirates(?) :))

4. Supplied at least on executable to an anti virus scanner to see if it's
not infected, nothing found.

5. Run these tools which I will here not further specify to investigate the
"casual" bios settings/options and what not via gui. This bios has many
features. The rom image is exactly 1MB which is quite large for my taste ;)
Nothing irregular found with the tools so far.

6. I tried to export some rom information, and tried to reverse/dissassembly
some parts of it, this was unsuccessfull, ida pro doesn't recgonize it, it
doesn't know where to start and neither do I. It tries to analyze it as Z80
?!? I set it to x286, or athlon etc, but it still doesn't know where to
start.

7. I also looked at some "hackers" tutorial how "he" does things... hackers
doesn't explain how to reverse engineer some things... he did mention the
following:
"SingleLinkArch" is the main rom section of the bios ? (Hacker was trying to
do something with keyloggers/anti keyloggers)

8. I also already noticed myself there is something called a "bootblock" I
wonder if it contains any "cpu fan" related instructions ?!?

9. I also figured out reverse engineering it wasn't going to provide me with
lot's of data unless it was in c source or pascal like form... mostly it
would be in asm language form which would/could be difficult to understand.

So I went back to the original plan:

10. Trying to run it in a simulator, this was actually the first thing I
tried but AMD SimNow 4.4 doesn't allow to create a system, so I went to AMD
site to see if something better/newer is available. AMD SimNow 4.5.2 is now
available and does allow to create a custom virtual pc. Unfortunately for
me... I do not yet quite understand how to do that because it requires to
attach some kind of devices together which I have never heard of ?! ;) :)

This time AMD SimNow 4.5.2 does come with some system images, but these seem
to be weird hardware systems... I am not sure if it actually contains a PC
system ?!? Which is kinda odd...

11. I also tried to use the weird systems with my bios rom image... The AMD
SimNow 4.5.2 needs to know the size of the rom image in 32 KB chunks... I am
guessing it's 1024/32 = 32 ?!?

12. It also needs to know the "base address" or "entry address" or something
like that into the BIOS image... I am not sure what that value would be, or
how to find out... so that's something that would be needed to figure out in
the future.

However I decided before I was going to try and get a system working in full
it would be smart to simply load the pre-installed systems and see if there
is such a thing as a cpu fan indicator/device or variable or whatever.

13. This seems not to be the case... So the funny thing is: "The cpu fan"
can now be simulated... thus a crucial system component is actually not in
the simulator which is kinda amuzing to me... It's also not really that
surprising and it also explains a lot... It explains how a cpu fan
failure/bug might have gone unnoticed ;) :)

14. The last thing I did (actually before I noticed the cpu fan simulation
is missing) was sent a message/response/feedback to AMD support to explain
my problem, my goal and asking if it was possible... I guess for now with
the current version it's not possible.

So end conclusion:

For now I will have to wait with the bios analysis until:

1. AMD SimNow gets CPU FAN device support/emulation.

2. AMD SimNow comes pre-installed with a realistic pc system scenerio ! ;)
:) Preferably Asus A8N32-SLI/AMI BIOS like system with Athlon Processor ;)
:)

Bye,
Skybuck =D


 | 
Pages: 1
Prev: Call for papers (Deadline Extended): HPCS-10, USA, July 2010
Next: Multi-core lag for Left 4 Dead 1 and 2 and Quake 4 on AMD X2 3800+ processor... why ?