My installation is in /usr/lib and I clicked on Help>About Firefox and it downloaded and updated to version 8.01. and all seemed to be working including existing flash 10.
However, when I closed and restarted Firefox8, flash wasn't working and rendering of web pages was flakey.
It seemed to me that the only reason this could happen would be environment setting failure. Looking in the Firefox folder, I found two firefox binaries, almost equal in size.
Normally, the file "/firefox/firefox" is a script which sets up the environment and then starts "run-mozilla.sh" and finally "firefox-bin". So, this meant that the "/firefox/firefox" binary download update overwrote the "/firefox/firefox" script file.-rwxr-xr-x 0/0 55664 2011-11-04 20:54 firefox/firefox
-rwxr-xr-x 0/0 55668 2011-11-04 20:54 firefox/firefox-bin
I then reverted back to firefox6, renamed the "/firefox/firefox" script to "/firefox/firefoxHOLD"
and then allowed the automatic update again. After it updated, I renamed the newly downloaded "/firefox/firefox" binary to "/firefox/firefoxNULL" and renamed the script file "/firefox/firefoxHOLD" back to "/firefox/firefox".
Now, when Firefox8 is run by the firefox script file, everything works as usual.
Cheers,
s