@fossfreedom: I have replied in this topic: How to install Ubuntu on a IBM R31 Thinkpad
I thought I posted valuable, additional information to a reply from Steeldriver. However, my post/reply was deleted.
If it was because it looked like hyjacking someone else's post, I apologize for that. This was not what I meant to do.
I posted my message because I think it contains more information which may help to solve the Original question from David Taylor.
(Steeldriver wrote about the boot options on a similar thinkpad x30, which has boot from usb support, the thinkpad r31 seems to have fewer options in the bios / boot menu)
So I believe my post was deleted for the wrong reasons and my post was intended to help to solve the Original issue (which I am having too)