How to change the device id of a VBIOS

[Bao, Zheng]

Some of the VGA modules have almost same function and vgabios. The only
difference is the Device ID. I am wondering, if I got a Vgabios for
graphics card A, can I just change the device ID in the binary file to
fit the graphics B? Is there any checksum in the vgabios.bin? Is there a
tool to handle it?

Zheng

[Peter Stuge]

Bao, Zheng wrote:
> I am wondering, if I got a Vgabios for graphics card A, can I just
> change the device ID in the binary file to fit the graphics B?

If the code is the same, sure.
> Is there any checksum in the vgabios.bin?

Yes. Option ROMs follow a well defined standard.
> Is there a tool to handle it?

Try tools/buildrom.py in the SeaBIOS repository at
git://git.linuxtogo.org/home/kevin/seabios.git

http://git.linuxtogo.org/?p=kevin/seabios.git;a=blob;f=tools/buildrom.py

//Peter

[Joseph Smith]

On Fri, 25 Jun 2010 09:06:23 +0200, Peter Stuge  wrote:
> Bao, Zheng wrote:
> > I am wondering, if I got a Vgabios for graphics card A, can I just
> > change the device ID in the binary file to fit the graphics B?
>
> If the code is the same, sure.
> > Is there any checksum in the vgabios.bin?
>
> Yes. Option ROMs follow a well defined standard.

Hello,
I had to do this to get my i810 vbios running on i810e because they have
different device id's but use the same vbios.
So what I did is just use a hex editor and change the device id to the
correct one. But then SeaBIOS would complain about the incorrect checksum.
I used Kevin's buildrom.py utility which basicly clears the lower 4 bits of
the checksum which should be a 16 bit register at 0x07.
This worked great for me, hope it helps you.
> > Is there a tool to handle it?
>
> Try tools/buildrom.py in the SeaBIOS repository at
> git://git.linuxtogo.org/home/kevin/seabios.git
>
> http://git.linuxtogo.org/?p=kevin/seabios.git;a=blob;f=tools/buildrom.py