Trackpad firmware doesn't update and now stopped working (Lion & MacBook 13 Unibody late 2008)

Hi,

I bought an oldish MacBook 13' Unibody (late 2008) and when I got it one of the first things I did was to install Mac OSX Lion.

Everything was working fine, until I applied an update that made the trackpad stop working (it only accepts clicks, no touch is recognized).

This is the "Trackpad Firmware Update" from the automatic updates.

When starting this firmware update it appears a window with a status message, cancel and Update buttons. After clicking the update button, it starts installing, appears to complete, status changes to "Finishing...", and Update button comes back active at some point.

After that I have tried (unsuccessfully):

• downloading and installing the update directly from Apple Support (http://support.apple.com/kb/HT3288)
• same thing, but using the 'root' account
• leaving the computer on overnight to see if actually "finished" the process
• Reset PRAM PVRAM - http://support.apple.com/kb/HT1379
• Reset SMC - http://support.apple.com/kb/HT3964
• Hand palm pressing over 30 seconds on the trackpad (read this on another thread...?)

Any ideas?