I bought an unlocked TMo Pearl to use with Cingular about 6 months ago.

I had issues with the ringer not working, which was usually fixed by taking out and putting back the battery (this happened many times). At some point that no longer became an issue but now I cannot hear anything when I make calls directly on the phone (phone to ear), so I am limited to making calls via my hands-free or speakerphone. This issue has not been fixed no matter how many times I reset the battery.

I have not been able to find any threads addressing this issue in the forum. I realize that upgrading the OS may help, but before I do anything like that (I've never done it before), I was wondering whether I should wipe my phone first? I know it's not required, but considering my particular problem I was wondering if this would be recommended...

Also, in case this *cannot* be fixed and I have to get a new phone, considering I got it unlocked, would I be able to get a replacement from Cingular or RIM?

If anyone has had the same issue, I'd appreciate any feedback or advice!

I haven't had that issue (as I don't have a 8100) but I would definitely wipe the device completely prior to loading a new OS. I actually do that all the time (when I upgrade) then I load the programs on after that. I am just like that, I guess.

But I probably would recommend you update the handheld OS. That would be my next logical guess.