I tried SLAX instead of KNOPPIX and had no hardware issues. SLAX is much smaller, easily fits on a USB thumb drive, and should have all of the tools you need for recovery work. In general KNOPPIX is a much more complete system, but is not as up-to-date as some other Live-Linux systems.

If you are working on disk recovery, the best approach is to clone the disk content to a new driver, then work on file recovery using the new drive. There are some tools for this that try to read the good parts of the disk first, such as dd_rescue. SLAX has add-on modules, so you will need the "ddrescue" module.

Here is an example of recovery using dd-rescue.