First I tried using the application manager as found here:
https://wiki.mozilla.org/Mobile/Fennec/Releases

That failed so I gained root and I uninstalled xulrunner and fennel.

dpkg -r xulrunner
dpkg -r fennec

Next I retrieved the debs at:

ftp://ftp.mozilla.org/pub/mobile/dis.../binary-armel/

and installed:

xulrunner_1.9.1b1pre-20080923171103_armel.deb

followed by

fennec_0.8_armel.deb