Spoofing the OS to the BIOS

In the past, I used a Tyan MP2466 dual-processor motherboard and noticed something odd about it over the years. I had instability problems where it locks up so that only cycling the power switch will restore it to function. It seemed related to video and USB devices and IRQ's, but maybe not. I've also dual-booted to WinXP to play some of my games that won't run in Linux and noticed that I never had the same instability problems with WinXP on the very same hardware.

All that seems over now. A kernel command line option, acpi_os=, will spoof the Operating System to the BIOS. The available choices are found in uteval.c in the kernel source. If using a Microsoft OS, any value prior to Windows7 returns the value for Windows7. Here is the current list:

"Microsoft Windows" will spoof for Windows98
"Windows 2000", /* Windows 2000 */
"Windows 2001", /* Windows XP */
"Windows 2001 SP1", /* Windows XP SP1 */
"Windows 2001 SP2", /* Windows XP SP2 */
"Windows 2001.1", /* Windows Server 2003 */
"Windows 2001.1 SP1", /* Windows Server 2003 SP1 - Added 03/2006
"Windows 2006", /* Windows Vista - Added 03/2006 */
"Windows 2009" will spoof for Windows 7
"Windows 2012" should spoof for Windows 8
"Windows 2013" should spoof for Windows 8.1
"Windows 2015" spoofs for Windows 10
"Windows 2016" spoofs for Windows 10, version 1607
"Windows 2017" spoofs for Windows 10, version 1703
"Windows 2017.2" spoofs for Windows 10, version 1709
"Windows 2018 " spoofs for Windows 10, version 1803
"Windows 2018.2"spoofs for Windows 10, version 1809
"Windows 2019" Windows 10, version 1903
"Windows 2020" Windows 10, version 2004

Quotes are required!

Additional values for more recent version of Windows can be found in my other blog post.

While it's pretty esoteric stuff, the identity of the OS can determine how the BIOS identifies hardware to the OS.

Interestingly, using acpi_os_name=Linux as a default is not allowed since hard-coded work-arounds for Linux in the BIOS cannot be undone even if the error is fixed in a BIOS update.

Using the de-compile method from here, I can see that my current system supports Windows 98, NT, XP, Vista and 7.

I now pass acpi_os_name="Windows 2009" to the kernel .

This general use of this option seems to be most likely useful for Linux laptop owners who would spoof to the version of Windows that the manufacturer shipped with the laptop.

RESOURCES

Microsoft Hardware Developer Doc

ACPI BIOS Guideline for Linux

ACPI provides two mechanisms for determining the OS

Comments

DOS4GW.EXE Version 2.01a and Alternative DOS Extenders

DOS4GW.EXE The Tenberry DOS extender DOS4GW.EXE was used by many early DOS games. I still enjoy playing many of these games and DOS4GW.EXE is usable with DOSBox , so they can be played on Linux. However, the version of DOS4GW.EXE that was included with the game was whatever was current at the time. The most recent version that includes many bugfixes that possibly affected the games when used with DOSBox have been fixed in the latest version, 2.01a. It's not free at US$49, but you can downloaded it here . Simply substitute it for whatever version of DOS4GW.EXE your game provided and enjoy the bug-fixed goodness. Tenberry also makes a "high-performance" "pro" version of DOS4GW.EXE, but it costs $300. I think that they could sell quite a few of these to hobby users (since, you know, DOS is dead) for US$5. Open Souce to the Rescue There are better performing, free and Open Source alternatives available and worth a look. DPMI Explained Let's unders...

Return to Castle Wolfenstein for Modern Linux

Return to Castle Wolfenstein is a first-person shooter originally released on November 19, 2001. The game, like many other classic games, is available at GOG.com and costs only US$5.99. iortcw for Linux Don't bother with old and crusty Linux binaries offered by idsoft; they are problematic and it's painful to use them on a modern Linux. Fortunately for us, there are more modern GPL-licensed Linux binaries available for 32- and 64-bit systems as well as high resolution textures packages. The project at GitHub provides source code that can also be compiled for MS Windows using MinGW. iortcw for Windows and Mac You can download pre-compiled binaries for 32- and 64-bit Linux, MS Windows and Mac from here . Let's put our files in /usr/local/games/rtcw . As root, extract the downloaded .ZIP file for your architecture to /usr/local/games/rtcw . All we are missing are the game data files. I purchased them from GOG.com. The game installer downloaded from GOG.com can be ...

Unreal Tournament GOTY/UT99 for Modern Linux

Released on November 16, 1999, Unreal Tournament (also known as UT99) is an arena first-person shooter for Multiplayer on-line competition or you can play against bots off-line. It features several game types, with more details provided at Wikipedia . The game was re-released on February 25, 2000 as Unreal Tournament Game of the Year Edition (GOTY) which included the three bonus packs released previously and additional mods, or game modifiers that had become popular. It is the GOTY version that is available from STEAM or GOG.com . The GOG version for Windows installs in Linux and plays well using WINE , PlayOnLinux or Codeweaver's Crossover . There is a Linux binary available in two versions, one for the original game and one for the GOTY edition . Also provided at that site is the Official Bonus Pack with a Linux installer. All these Linux installers are created with makeself . There are some issues using such a crusty old Linux binary. Let's see why getting...

MaximumHoyt

Search This Blog