I wrote the BootROM and 2nd stage loader used in VC3 and VC4 - way back in ~2005. And the interrupt controller, VPU sync block and various other things used in this open FW.

This is pretty awesome to see how much context the community has reverse engineered from the design - I remember making the first BCM2835 based project (the Roku 2) and spending _A LOT_ of time getting the ARM to startup reliably and boot into Linux as fast as possible. I've spotted 2 concepts in the open FW so far that misunderstood the implementation of the HW but are still working which is fun!

One advantage of the having the GPU start first (maybe the only advantage :) is that it can play a video for a splash screen instead of a static image. If you've ever used a Roku 2/3 or newer, this is a feature I hacked together for a demo to hide boot-up latency - now its a standard part of RokuOS (and is quite hard to replicate on traditional ARM/MIPS SoC's).