New in-development public version is available for download at
http://tny.im/hP
Two-point changelog: addition of calculator lock feature and little improvements in text input.
Calculator lock works more or less the same way as my previous calculator lock add-in, except that this one doesn't use sprites at all, allows for a numeric code of up to 255 characters (no letters/symbols allowed as of yet, anyway they aren't very practical to type) and uses the system calls for text input minus GetKey (as that allows for getting to the Menu).
The code hash is stored in both main memory and storage memory. If you delete/modify the code hash in one of the locations, expect a "data mismatch" warning and having your calculator "permanently" locked until you reboot.
To set a new lock code after you set one once, go into Setup (Shift+Menu) and select "Set calc. lock code". For locking the Prizm press F4 in the home screen.
To unlock the calculator (when it says "Calculator locked" at the bottom right), press Alpha. To power it off at said screen, press Shift+AC/ON (both individual presses and simultaneous presses, for those used to my previous add-in, are supported).
More settings and functionality will be added to the calculator lock system at a later point. (By the way: if someone found a way to start an add-in/run custom code at calculator startup, without modifying too much the OS, it'd be awesome).
About the text input improvements, it's very simple: lowercase is now properly signaled in the statusbar, and you can now insert single Alpha and lower-Alpha characters without getting into Alpha-lock mode (just by pressing Alpha without Shift before). This is also properly signaled in the statusbar.
I think text input now behaves in the exact same way as the input the OS provides.
Please tell me if you find any bugs.