for anyone who is wondering SDXC 64gb cards do work in the surround, I had originally done the 32GB upgrade, and now have moved up to 64GB running the nokia rom have not found anything unstable etc, its just as fast as it was and everything works fine
Linux Planet: "Canon's digital cameras, like all digital cameras, are really little computers. Certain features are enabled or disabled to justify different price points. It's all done in software, so the wizards of CHDK have created firmware to add new features (such as RAW support), and to do it safely without bricking your camera. Akkana Peck tells how in part one of this series"