I've installed BT4PF on my ext hdd through ubiquity.
Everything else is persistent except that the keyboard layout reverts back to the default US (mine UK) everytime it is rebooted.
I've tried to use the following command but to no avail
'# dpkg-reconfigure console-setup'
I've a ThinkPad SL500 and btw, during boot, it says 'not yet supported ThinkPad detected'