I was able to deposit a check through Deposit@Home on Lucid by:
1. Uninstalling Icedtea Firefox plugin and Installing Java Firefox plugin
2. Installing Xsane (Simple Scan does not have greyscale option)
3. Installing HeaderControl Firefox addon and setting the user agent for usaa.com to be:
Then just login to USAA and follow the instructions on the Deposit@Home section. The site will think you are on a Mac everytime you go to it, bypassing the system requirements. You will then scan in your checks with xsane and upload them to USAA. Make sure they are 200 dpi and greyscale.
Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:220.127.116.11) Gecko/20060426 Firefox/18.104.22.168