What OS versions have you tried. 4.5.0.131 is stable and relatively problem free. It doesn't suffer from the speakerblast problem like .77 does.
Unless you can find the thread here with a download link, you might be better off searching for the Telus version of .77, it came up in a search I did a while back.
If you can't find it, I can download the installer file on my PC to a filesharing site for you, but you will have to wait till I get home from work (I just started).
FYI, whenever you download an OS, keep a copy of the installer file somewhere on your PC. If you ever need to install that OS again, it is as easy as launching the installer for that OS version. I have a copy of the installer file for every major OS released for the 8330.