So I got distracted by the freshly added USB feature, and I adapted the USBaspLoader (to be precise a more up-to-date fork by Stephan Bärwolf), this bootloader is compatible with avrdude. I think the only changes needed were pin assignements, and like 6 lines in the main include to add support for atmega128rfa1 (copy-pasted from atmega1284 because they're almost the same, except for the radio part). And it worked right away. And it's actually faster than the hardware ICSP dongle I was using.

Then I spend more time crafting nicer and more convenient to install USB port boards...

But eventually, I got around to implementing the status bar: it lists battery status (as in voltage), current page, size of the current page in bytes and words(for NaNoWriMo), and gives a rough estimate of your place on the page.

Function keys are now:

• F1: save and power off (sleep).
• F2,F3: contrast adjust
• F6: delete(click 3 times)
• F7: undo all recent edits
• F8: export page as one or more QR codes
• F9: sleep
• F5,F10: previous/next page

The project is now published on github. Though the code is a mess.

To do:

• Better exporting. Either optimize the hell out of the QR codes, or more likely implement some less computationally expensive coding and make a reader app for it.
• Export via USB maybe.
• Better storage handling. On the other hand, the current approach has a certain je ne sais quoi about it... maybe it is the way it feels more like pages in a notebook than files in a computer. YMMW.
• Probably some copy-paste function.
• feature creep?