Thanks for putting some time and effort into a screencast, much appreciated

As you've pointed out, this happens when your locale is set to a non-Unicode language, which is indeed because of CONFIG_FEATURE_CHECK_UNICODE_IN_ENV being set to y.

Because this is default behaviour; not only in BusyBox, but also in other shells like Bash. Why would you want want your shell to use a different locale than you've set up in your OS?

Of course, on the N900, this is highly debatable, considering UTF8's superiority to ASCII and the fact that it is backwards compatible with it. There isn't any real reason on the N900 to use a non utf8 locale for its shell. I'll consider setting CONFIG_FEATURE_CHECK_UNICODE_IN_ENV to false, if nobody can come up with any disadvantages/possible issues with doing this.

Edit: By the way, setting the config option to false does fix the original issue, but that was to be expected (as it basically forces the use of Unicode).

I've noticed this too, but after a quick recompilation with CONFIG_UNICODE_PRESERVE_BROKEN=n, '?' continuous to be shown upon pressing Ctrl-Space. This is probably because Maemo is not made with a proper Unicode implementation in mind, at least not for its shell; the stock BusyBox' Unicode handling doesn't even work correctly when the locale is set properly. Any hints on this one are appreciated