Or anything else to do to prepare the installation files?

No and no.
Focus on the drivers you need.
Especially lan so you can get to windowsupdaterestored
The voodoo might not work on a system so fast

That motherboard is based on the Intel P965 chipset which has no Win98 support.
If the hard drive is in IDE mode you can probably still install Win98 ok but nothing onboard will work.
As well as installing the S3 Virge you'll need to install a sound card, Network, USB which do have Win9x drivers.

512MB ram doesn't require patching
LGA 775 is also old enough that you shouldn't need to use things like patcher9x, however as you don't have chipset drivers you'll miss out on things like DMA.
If it was me I'd do a test Win98 install on an old spare hard drive and see how well it performs, as its Definity not an ideal system but may be enough for your needs.

Everything except for sound works btw. I managed to install ICH8 drivers from https://retrosystemsrevival.blogspot.com/2019 … ers-9x.html?m=1 so I have full chipset support.
Could install all other drivers, too and playing an old 3D game with the Voodoo2 just works! Nothing seems too fast in fact.
Now I am trying to get sound going with this crazy approach to use an old Win 3.1 driver over at MSFN.

Also: thanks for pointing me to windowsupdaterestored. However, I was wondering which benefits an unofficial service pack (3.2?) would bring? Where's the best place to download that one? Thanks.

Dr.Atom wrote on 2024-07-15, 06:25:

However, I was wondering which benefits an unofficial service pack (3.2?) would bring? Where's the best place to download that one? Thanks.

Nothing except of a lot of bugs. Versions prior to 3 can be useful though.