Well, the ARM is literally powered down until the VC4 turns it on.
(I've heard that the only reason the ARM is there at all is that Broadcom had a royalty-free license and there was some spare silicon, so they thought, hey, why not, it might be useful...)
Traditionally ARMs have never used any kind of common boot process because they come out of the embedded world where every system is bespoke --- the focus is always on individual products, rather than building a platform.
There have been various efforts to fix this but AFAIAA they've never come to much. I think the current one is DeviceTree, but I don't believe there's much vendor support.
(I've heard that the only reason the ARM is there at all is that Broadcom had a royalty-free license and there was some spare silicon, so they thought, hey, why not, it might be useful...)
Traditionally ARMs have never used any kind of common boot process because they come out of the embedded world where every system is bespoke --- the focus is always on individual products, rather than building a platform.
There have been various efforts to fix this but AFAIAA they've never come to much. I think the current one is DeviceTree, but I don't believe there's much vendor support.