The previous dualboot scheme had a major flow: it needed to hold
menu to boot OF but the X-Fi2 boot in recovery mode with menu!
It was possible but very trick to enter the OF with USB plugged.
This code provides a new scheme:
- no USB plugged: boot to OF when menu is pressed
- USB plugged: boot to OF when power is pressed
Change-Id: Ia6e76d3ada1f67137b727daa050cf6c77afbbfb9
Only boot to rockbox if the power button is hold sufficiently long.
For consistency, use the same mechanism as the OF:
- read PSWITCH 550000 times
- boot if PSWITCH=1 at least 400000 out of 550000 times
Only apply the delay if Volume Down is not hold,
so that the OF and RB delay don't cumulate.
Change-Id: I1e8a4cd108c56bf784fcf1c320f7a001ef161701
