Have you updated to the latest kernel zImage and modules? From
http://glemsom.users.anapnea.net/and...htc-msm-linux/
I ask because once I did that not only does sound work, but it makes the earpiece volume MUCH louder. Actually TOO loud, because it crackles/distorts/clips a bit when the other side says something loudly. But I believe they're still working on that. Its still much better than when the sound was too quiet to use.
But to answer your question, no there currently isn't any way to change it to my knowledge. But as I said, the default is much much louder.
Edit: And it looks like theres already a quick-and-dirty fix for it being so loud it causes distortion. Available here:
http://sites.google.com/site/android...llvolumeupdate