<clever>
belgin: to explain some stuff i couldnt on wed, the boot rom on the pi0-pi3 family, can boot from the 8 sources listed here
<clever>
1/2/4 are all booting from bootcode.bin on fat32 on SD, just with different SD controllers or modes
<clever>
3 is raw nand flash, i only know of that being used on the roku 2 xs
<clever>
5 is SPI flash mode, the pi4/pi5 also support this, and thats the primary way of booting
<clever>
6 is usb, for the pi0/pi1/pi2/pi4/pi5, it only supports usb-device mode
<clever>
for the pi02 and pi3, usb also supports a usb-host mode, where it will run in either MSD mode, or ethernet mode, and then download things via tftp, or bootcode.bin on fat on MSD
<clever>
7 is i2c-slave mode, you just write a 24 byte header, and then the full bootcode.bin over i2c
<clever>
pi4 dropped things to just one sd mode, spi flash, and usb-device
<clever>
pi5 supports the same, but i cant confirm things 100%
<clever>
belgin: that all make sense?
<belgin>
yes, thank you very much, clever
<clever>
for the official bootcode.bin, it will try to load start.elf from the same device the rom got bootcode.bin from
<clever>
but if it was loaded from SD, and the SD is missing all other files, it falls back into usb-host mode
<clever>
this allows a pi0/pi1/pi2 to do usb-host (MSD or tftp) boot, despite the rom lacking support
<clever>
i lean on that as a crutch when doing open firmware development
<clever>
i can just shove a start.elf on tftp, and netboot it on any model
<clever>
but i have since added tftp and msd support to the open firmware
<clever>
so i can do that entirely down the open path as well now
<belgin>
cool!
<clever>
the main thing missing from the open firmware now, is