[TUT] Patch VPC 2007 to fix the Korean DOS rendering

[Battler]

So, as many of you have noticed, Virtual PC has a problem when rendering Korean DOS. Basically, it renders its 640x400 resolution as a double-sized 640x200 rather than as actual 640x400. This also affects the usage of the keyboard arrow keys in that resolution.

But, there is a way to fix it.

Open the Virtual PC.exe file (which is identical between the x86 and x64 versions) and change the following bytes (note these offsets are for Virtual PC 2007 version 6.0.156):

Code: Select all

Offset  : SS DD
---------------
0008C957: 75 EB
000D6B55: 74 90
000D6B56: 3F 90

These are the offsets for Virtual PC 2007 version 6.0.192 (SP1):

Code: Select all

Offset  : SS DD
---------------
0008DA67: 75 EB
000D7BA5: 74 90
000D7BA6: 3F 90

These are the offsets for Virtual PC 2007 version 6.0.210 (SP1) (thanks to TheCollector1988 for these):

Code: Select all

Offset  : SS DD
---------------
0008E707: 75 EB
000D8A85: 74 90
000D8A86: 3F 90

Where SS is the byte as it actually is in the file and DD is the byte you need to change it to. Offset is just that, offset to the byte.
Basically, this patches Virtual PC 2007 to not treat the 640x400 resolution as a special case and instead reander it "as is", that is, as 640x400. This makes Korean DOS work properly on Virtual PC 2007. The same should also be achievable on other Virtual PC versions, differing only in the offsets to the bytes.

However, BEWARE: this will make the actual 640x200 resolution render incorrectly, so make a backup of the unpatched Virtual PC.exe file (or just make a copy of it and patch the copy) so you can use it to run anything that needs the actual 640x200 resolution.

And here is a screenshot of Korean MS-DOS 6.00 Setup in the patched Virtual PC 2007:

[TheCollector1988]

Not to bump the thread but here's an update (for Virtual PC 6.0.210 only)

offset: 8E707h (for 75)
offset: D8A85-D8A86 (for 74 3F)

[Battler]

Here are the offsets for 6.0.192:

Code: Select all

Offset  : SS DD
---------------
0008DA67: 75 EB
000D7BA5: 74 90
000D7BA6: 3F 90

.

Enjoy!