TCU does faint flash of top blue led after power button pressed ?

[phil_h]

(Associated with my recent post about 'Power On 'Emergency' Mode ?')
Press power button as normal, the top blue led flashes faintly, then all leds display as normal, the power level circle displays for a second, then it shuts straight down.
What is this faint top blue led about ??? Is it a clue ?
If I disconnect the handlebar remote cable, exactly the same happens.