How to enable execute-disable bit and other hidden settings on Lenovo 3000 N200 model 0769!
Here's some good news for anyone with a Lenovo 3000 N200 model 0769, who is disappointed and frustrated with the lack of options in the BIOS setup menu. (I had a moan about that in this thread.)
This is a long post but I hope you'll find it worthwhile. Here are the features/settings which I will explain how to enable:
The BIOS disables the execute-disable bit function of the CPU, with no way to turn it on. You can enable it.
You can set VGA and VESA graphics modes to not be stretched to fill the whole screen (sharper graphics with no distorted aspect ratio).
Speed up the POST display by skipping the memory test
Disable various features (if you don't use them, that might save some power): the HD audio controller, WLAN card, on-board LAN, shadowing of the video BIOS
Enable beep before booting the OS
Enable key click sound (only in DOS, not Windows or Linux)
I'm still working on this, and hope to figure out more hidden settings soon, e.g. to disable the DVD drive and trackpad, and to change the video output from NTSC to PAL.
The information below applies to the Lenovo 3000 N200 model 0769 with BIOS version 3.03. My N200 has Nvidia graphics. For some background on the general principles/research required to figure this out, please see this thread at Wimsbios.com.
To change the settings, you need to create a bootable DOS floppy disk or USB drive. Download SYMCMOS.EXE (Google for it) and put it on the bootable disk. Boot the disk and run SYMCMOS to back up your current CMOS settings: SYMCMOS -Lsettings.txt
Next load the settings.txt into a text editor. It will begin like this:
( SYMBOLIC CMOS EDITOR - Version 643710-035 )
CRC = 3EDD
Your CRC value may differ. Each line after the CRC contains a token number, followed by the value of that token. You can start with the settings.txt you created and edit any tokens you want to change, or delete all token lines and just include the tokens you want to change. Then use SYMCMOS.EXE to apply the new file: SYMCMOS -V2 -Uupdate.txt
After running that command you can reset, and hopefully notice the new settings in action. (For certain settings, such as re-enabling the execute-disable bit, you need to turn the computer off then on again.)
Here are some specific tokens you can change:
Token Default New Description
(0000)   Disable the HD audio controller
(0042)   Disable LCD panel graphics scaling/stretching
(004B)   Beep before booting the OS
(0267)   Enable support for the CPU execute-disable bit
(028E)   Enable key click (only works in DOS and BIOS setup)
(02A3)  Set to 0 for slower memory test, or 2 (or 3?) to skip
test for faster booting, especially with 4GB RAM
(046E)   Disable video BIOS shadowing. (Best to leave enabled.)
(0471)   Enable 1MB memory hole at 15MB. (Best leave disabled.)
(0486)   Disable PCI Express ports 1-6. This takes precedence
over the individual port bits below, and disables the
LAN, WLAN and (probably) ExpressCard port.
(0489)   Disable PCI Express port 2 (WLAN card)
(048C)   Disable PCI Express port 3 (maybe ExpressCard?)
(048F)   Disable PCI Express port 4 (LAN)
For example, if you want to disable LCD panel scaling and enable the execute-disable bit, you would create a text file like this:
CRC = 3EDD
Some final points:
Loading the default settings in the BIOS setup menu will overwrite any changes you make using SYMCMOS.EXE. So keep that bootable disk around in case you need to re-apply your settings in future.
The token numbers above are specific to version 3.03 of the Lenovo 3000 N200 model 0769 BIOS. They might be different for earlier BIOS versions, and will be different for other models of computer.
Once you have created a bootable floppy disk with a text file containing your updated settings, you could create a bootable CD with the floppy's data on. Just boot that CD to restore your settings in future.
Before experimenting with randomly changing token values to discover other hidden settings, make sure you know how to reset your computer's CMOS memory! Changing some settings results in your computer becoming unable to boot, so you can't use the BIOS setup screen to reset. I wrote about how to reset the N200 model 0769 CMOS in this thread.
If you discover any other settings, please let me know.
Any changes made are at your own risk; if you "brick" your laptop don't blame me!
Message Edited by Donuts on 10-15-2008 09:45 AM
Message Edited by Donuts on 11-16-2008 11:35 PM
Hi Donuts !
My computer is a 3000 N200 0769BAG. It has a Dual Core Pentium and the information I get about the BIOS using lshw are :
physical id: 0
version: 68ET35WW (04/16/2008)
capabilities: pci pnp apm upgrade shadowing escd cdboot bootselect edd int13floppy360 int13floppy1200 int13floppy720 int13floppy2880 int5printscreen int9keyboard int14serial int17printer int10video acpi usb ls120boot biosbootspecification
I've nothing telling me it is a 3.03 BIOS version but only got the BIOS file name (68ET35WW);
Is it the same BIOS you used and if not how could I find the list of (token, default value,new seting) for that particular BIOS ?
Thanks a lot in advance for your help !