So just to document my steps (as promised above) getting Spotify to work on my Pre 2 running HP webOS 2.0.1. And a BIG thank you of course goes to tfelgentreff who figured all of this out!
(Btw, I'm sure this would be pretty easy to do in a simple patch)
1) Install Spotify* on your Pre 2
*: Free app, but not available in all countries, don't think it's allowed to describe workarounds(?)
2) Install Novaterm on your PC (comes with webOS doctors or public SDKs)
3) Connect the phone using USB cable to PC, select "Just charge" on the phone
4) Run the script novaterm.bat from "C:\Program Files\Palm, Inc\terminal"
5) Select "Connect" and you are logged into your device on a Linux shell
6) Go to /tmp using cd /tmp and download the spotify.zip from tfelgentreffs post in this thread using something like wget http://demo.com/spotify.zip (I used my dropbox public folder for this)
7) Run cd /media/cryptofs/apps/usr/palm/applications/com.palm.app.spotify/resources and then unzip /tmp/spotify.zip
8) Run install script using ./install.sh
9) Copy the json files to the two extra locations:
cp /var/palm/ls2/roles/com.spotify.palmserver.json /var/palm/ls2/roles/pub
cp /var/palm/ls2/roles/com.spotify.palmserver.json /var/palm/ls2/roles/prv
10) Restart your phone, and you're done! (hopefully)
Bonus tip: Spotify runs FREE 7-days Premium trial just now, for all your testing needs...