I'm curious as well, and yes, by reboot I mean calling "reboot(RB_AUTOBOOT)". I was under the impression that the ROM code has to start over from the beginning, which I think it does. Maybe it can skip some initialization since the SoC is already up and running. Maybe there is some initial hardware setup that is only done at power on. It's hard to tell as this part of the boot sequence runs closed source NXP code.