Compiled deb packages have kindly been provided here: http://romaxa.bolshe.net/fennec/
Either download on your phone directly or dump it on there via USB. Next make sure to disconnect the USB cable and open up the terminal.
First we need root:
hit i for text entering mode and add the following repo:
deb http://harmattan-dev.nokia.com/ harmattan/sdk free non-free
hit esc to exit text-entering mode. The file is automatically saved. Doing so will add this source to the package manager apt. This particular repo gives us access to a library we need for installing Fennec, libpango, a library for laying out and rendering of text:
apt-get install libpango1.0-0
Now, it’s time to install Fennec:
or if you downloaded it on the phone:
(or whatever version you downloaded, just hit f and tab :) )
And it should run with no errors and the Fennec icon will appear in your home screen!
Original post on web.archive.org.