Busybox is not a Linux version (Linux is only the kernel), but an implementation of many of the basic commands. It's usually used where we have little space, to replace coreutils, util-linux, fileutils and so on, most of which comes from GNU. To my knowledge, all e-ink devices run Linux, but the userspace may vary a bit.
The shortcomings of the poterm keyboard come from inkview, and I believe poterm is also pretty useless for screen oriented things like curses (less, vi, top etc). The keyboard is defined in a config file (language/keyboard/EN.kbd) which may contain multiple layouts (although I suspect it's a fixed size), so we can probably add in the missing characters.
Edit: Almost forgot, great job! And by the way, I don't think there's a firewall but busybox' version of nc (netcat) doesn't have listen mode. Somewhere there's a telnetd we can build for the pocketbook.
Last edited by LoneTech; 01-14-2011 at 03:16 AM.