My full review of the firmware is at http://shkspr.mobi/blog/index.php/2010/03/elonex-511eb-firmware-update/
It is different from the previous version on their website – as evidenced by the version number and different checksums. The previous version was 0.41. I suggest you try downloading it again to make sure the old version wasn’t cached on your computer.
There’s no note-taking yet. That’s coming soon. I suggest people call Elonex to ask them when it will be.
OpenInkPot – http://openinkpot.org/ – is a Linux based firmware. The 511EB runs Windows CE. From the look of the website – http://openinkpot.org/wiki/Device/N520/Overview – no one is working on it. If you were to donate (either a unit or some cash) you might be able to get someone to work on it.