The initial reason we've chosen to create an "all-in-one" ISO image was to simplify further configuration of an automated installation with PXE / Answerfile.

We tried driver disks before, though in our special case of mellanox-mlnxen-alt and hardware without any other NICs, I believe it always ends up requiring manual intervention. I haven't found a way to load the driver disk in the installer that is not connected to the network.

I think, even though my approach requires a bit more effort, it can still prove useful in some cases.

Hi, I've recently tackled the same issue and can confirm @stormi's steps are enough to get things running. I have built the installimg using https://github.com/xcp-ng/create-install-image, and included the mellanox driver by modifying packages.lst.

echo "mellanox-mlnxen-alt" >> configs/8.2/packages.lst

I then modified the /opt/xensource/installer/repository.py python script to include:

<     _targets = ['xcp-ng-deps']
---
>     _targets = ['xcp-ng-deps', 'mellanox-mlnxen-alt']

Such created ISO provides mellanox-mlnxen-alt in both the installer and the destination system.