Real DOS-Mode Patch for Windows Millennium
By Reines [MFD]

Last Update: August 15, 2000

Introduction:

Did you ever wonder why Windows ME, which is based on the Windows 9x kernel, can't access Real DOS-Mode? Did you think that Windows ME architecture doesn't allow it?

Well, it seems that Microsoft simply decided to hide this option in Windows ME, for some unknown reason...

This patch will modify "IO.SYS", "COMMAND.COM" and "REGENV32.EXE" in order to unhide the Real DOS-Mode on Windows ME systems, resulting in a similar boot process to the one available in Windows 9x. This will allow, for example, to reach DOS directly by pressing "Shift-F8" at boot-up, to use "CONFIG.SYS" and "AUTOEXEC.BAT" before Windows loads, and to set up a startup menu.

This patch was tested only with the final release of Win ME (build 4.90.3000). It might be compatible with other (future or previous) builds as well.

Version History:

v1.3 - Allows patching of non-standard versions of IO.SYS and COMMAND.COM. This adds full compability with non-US editions of Windows ME and might also allow to patch other (future or previous) builds as well.
v1.2 - Allows patching of non-standard versions of REGENV32.EXE (for instance, on non-US editions of Win ME).
v1.1 - Initial public release.
v1.0 - Internal release.

Important:

If you are using a NON-US version of Win ME you will probably not be able to use versions prior to v1.3 as the files that are patched seem to be country specific. We have updated our current release to reflect this. If you use the US version then you will not experience any differences between v1.1, v1.2 and v1.3.

Installation Notes:

In order to install this patch, follow the instructions below carefully.

Note that whenever the instructions that follow refer to "C:\WINDOWS", you should specify the correct directory in which Windows ME is installed.

Stage 1:

Before applying the patch, complete the following tasks:

1. Create a temp directory and copy into it:

"C:\WINDOWS\COMMAND.COM"
"C:\WINDOWS\COMMAND\EBD\IO.SYS"
"C:\WINDOWS\SYSTEM\REGENV32.EXE"

2. Make sure that the three files are writable, by running from the temp directory:

"ATTRIB -R -H -S *.*"

Stage 2:

When you complete the tasks above, execute from the temp directory you created the included patch:

"WINMEDOS.COM"

Stage 3:

Once the patch completes successfully, perform the following tasks in order to complete the installation:

1. Copy the patched files to their destination, overwriting the original ones:

"IO.SYS" to "C:\"
"COMMAND.COM" to both "C:\WINDOWS\" and "C:\"
"REGENV32.EXE" to "C:\WINDOWS\SYSTEM"

2. Edit "C:\CONFIG.SYS" and "C:\AUTOEXEC.BAT" changing them as described below:

Add to "CONFIG.SYS" the line: "DEVICE=C:\WINDOWS\IFSHLP.SYS".
Add to the bottom of "AUTOEXEC.BAT" the line: "C:\WINDOWS\WIN.COM".

That's it! Once these tasks are completed, DOS will be ready for use on the first reboot.

Additional Notes:

In case you wish to create a startup menu that lets you choose between Windows and DOS at boot-up, it can be done by editing "CONFIG.SYS" and "AUTOEXEC.BAT". The syntax of the startup menu is identical to the syntax on Win 9x systems. Keep in mind that the option configured to launch Win ME has to include the appropriate lines that load "IFSHLP.SYS" and run "WIN.COM" (as shown above).
Instead of editing your own files to create a startup menu, you can copy the "CONFIG.SYS" and "AUTOEXEC.BAT" included in this release to "C:\". These files provide a convenient configuration of a startup menu. If Windows ME isn't installed in its default path ("C:\WINDOWS") on your system, make sure to edit these files before using them so that the paths of "IFSHLP.SYS" (in "CONFIG.SYS") and of "WIN.COM" (in "AUTOEXEC.BAT) are specified correctly.
The line stating "Starting Windows Emergency Boot..." that you will see at startup has no effect at all on Windows. It appears because the patch is using the IO.SYS provided with the Windows ME Emergency Boot Disk.

Real DOS-Mode Patch for Windows Millennium By Reines [MFD]