Not for the faint oh or nervous hands. It requires using Surface Mounted Technology soldering tools.
It requires that one unsolder the two 256MB DDR2 RAM Chips (one on the back and on the front of the board) and replace them with 512MB DDR2 RAM Chips. As simple as that sounds, it is not an easy feat to do. One needs a steady hand to do this and a lot of time and patience to do it. But when it is done, it would be a great mod for the unit.
Here's the You Tube Video on how to do it:
https://www.youtube.com/watch?v=ux2U4yvx_Po https://lynda.videocloudpro.io/video/ux2U4yvx_Po/title?src=Youtube (Same video but explains why only one side was done.)