The ability to control the backlighting and other I/O, detect proximity event changes, handle positional data on the touch screen and graphically display buttons and localised language words on the buttons is F*CK loads of OS capability. It also plays music!

This is not impossible to work out the changable stuff then flash in to a limited little OS of it's own along with the firmware. You could hardwire what you expect the firmware to handle so it just runs some preprepared cpu instructions to trigger all the right stuff. I'm just amazed this is done.

It does make some more sense to configure the internal low power clock with a time to wake up the device, then try a very fast boot, not many init scripts, do the alarm capability and then on request to power up, just reset in to a full OS. It seems a pity to to utilised the booted kernel but the lack of runthrough of init scripts might make that more messy.

I'd estimate that it takes about 75% of the Linux based OS (maemo) to handle playing an alarm wav and pick up the screen pressed option. It's stupid to say £20 phone does the same, their OSes boot in 1-3 seconds and have trivial keypad button hardware, screen and alarm noise functionality so the firmware IS the OS.