The rpiboot software seems to be initially just for USB msd.
But it does seem to be getting usable as a way to load an OS into ram and run it.
Not sure it it will ever be the way to run full Raspbian on a Zero
Got a Cluster hat which takes four Zero's, one way to get 100 GPIO on a Pi2/3
Rpiboot could be extended into a tool for using Zero's as programmable USB gadgets for any Pi/PC/OS.
bootcode. bin and start.elf change too, newer ones are better, whoops 7 days ago, newer still
If we use Zero's as GPIO extenders we probably don't need the jpeg stuff which means using the cutdown versions - start_cd.elf etc. This means even faster booting as these are much smaller.
The possibilities of using Zero's for high speed ADC/logic analyzers, USB LCDs, HDMI displays, even parallel image sensors etc
Pi Camera is a bit more complex as it requires the start_x.elf versions plus the firmware. But raspistill/vid etc do run on piCore if a way can be figured out to load the required extensions.
Maybe Buildroot could be used to make a OS with everything loaded?
Raw-CSI is getting workable and latest firmware seems to be splitting out the ISP pipeline, baremetal camera one day?
At the moment Ultibo and other baremetal tools seem to be good enough to make a kernel.bin that can do GPIO stuff.
Just the four files are needed, bootcode.bin, start.elf, fixup.dat, kernel.bin. fixup.dat not really needed if you can live with only 256MB of ram, but it is not very big anyway. config.txt if any tweaking is needed?
Logic analyzer with 500MB of ram
I'm dancing on Rainbows.
Raspberries are not Apples or Oranges