It's not the firmware, drive or driver, well it may be the driver. I have a TEAC 40X and MJ shows the fastest burn choice as 24X. I think this is a bug with MJ. Like you, Nero allowed me to burn at 40X, after the MJ install that went down to 24X. I deleted all the burner info in Nero and J River in the Windows XP registry. Deleted the burner from device manager and rebooted. Now Nero allows me to burn at 40X but MJ still shows 24X as the fastest setting. I have posted twice, replied in similar posts and have IMed a developer and someone that may be the owner. I have had a few replies to posts with no real help and no response to the IM, one was just done a little while ago. At this point I have asked for a refund if no support can be gained.
I love the product and features; the ripping alone is why I chose the product. But when I pay $30 bucks I want all the features to work as advertised. I made sure the burner was on their hardware compatibility list and ran it unlicensed for a couple of weeks without issues. Once satisfied it did all that was claimed, I bought it. When the registration code was imported was when this started happening. When installed as shareware I could burn at 40X. I have uninstalled then reinstalled and ran the product with no registration key imported. 24X max burn speed. Reimported the registration code, same thing 24X max. This is very frustrating.