Earlier quoted context omitted.
And it's not just Linux. A little known fact is that during startup, before running a single instruction of Linux kernel code, the Pi spends the first several seconds booting the closed source OS that runs the weird Broadcom "VideoCore". Only then does it initialize the ARM processor and start the Linux kernel.
That's weird. I thought that VideoCore boots fairly fast.
Apparently rpi spends about as long on vc boot as it does for kernel+userland combined... Not great imho