It could be that those extra menus are triggered by the presence of a file (like the highres mode), which is put there at the factory and gets deleted afterwards - thus locking the functionality out and requiring physical access to restore.
Seems unlikely - at the factory they have a physical connection available so wouldn't need a way to configure via the keypad. I also doubt it would involve putting stuff on the user partition, as the settings could prevent access to this, though one possibility could be that it will only do it of it sees USB power.
Keeping it simple seems to me to be the most likely approach, not depending on anything that could be inaccessible under certain conditions
...How long until homebrew firmware running on this, with a better non-laggy UI and more functionality? The hardware doesn't seem all that complex to work with.
A possibility, but how much more functionality would there need to be to make it worth the effort? You'd also need to include their FPGA file, but if you left the factory filestructure in place, it would be in there anyway.
Assuming (as seems likely) the FPGA does most of the work and feeds a ready-to-display combined image into the camera interace it may not be a huge effort for someone who knows the processor. The main thing you'd need to figure out is how it talks to the FPGA and what data is passed - likely to be an I2C or SPI interface.
A potential issue may be getting the bootloader to load foreign code.
There is also the issue of figuraing out how factory cal data is dealt with.
.so what other functionality might be useful...?
Higher framerate is the obvious one, though may need a bigger lens to be useful.
Higher temperature resolution at lower framerate
Video recording, but memory capacity, and maybe CPU power for compression may be limiting.
Timelapse/ take pictured on motion detection (good for wildlife?)
Auto MSX distance detection ( may not have access to both datastreams though)
Some of these would be doable by plugging into PC/RasPi etc.
Not sure I can see it happenning.