You'll need to use an FTP program, and use the user ID and password of usr568603, the site name is totalservice.usr.com, just ftp there, and you will see the update file for the 568604. Download it, and then run the control center, use the flash from disk utility. Point it to the new .dmf file, and it will upgrade your modem. This solved some issues with mine, especially when I found out I was NOT getting anything but x2 connections with my ISP. I now get v.90 connections, and I'm not dropping off as much either.