DFU (Device Firmware Utility) is a host side (PC) utility and not residing on Edison
It is used for download firmware to device connected on USB.
On the Edison the boot components involved are
HW->Trusted Boot ROM -> IFWI ->Uboot -> Linux
Trusted Boot Rom which sits right on top of the HW: It is implemented as on-die silicon based ROM, and performs minimal hardware initialization and boots the IFWI firmware (Integrated Firmware)
IFWI (integrated firmware Image) - Contains firmware components required for initialization and operation of control units and accelerators within the SOC + first stage bootstrap
The first stage boot strap loads and runs the OS loader U-boot (second stage bootstrap to continue the booting of the Linux OS.
hope this helps in your understanding.
Thanks for the information, but there must be an Edison-side DFU (Device Firmware Upgrade) that dfu-util connects to to load the firmware. It looks to me like it runs before uboot, which means that you could blow away uboot and not brick the Edison. My question really is if I break uboot will I brick the Edison, or can I always re-flash it via DFU?
My personal feeling based on what I see during the boot sequence is that you should be able to restore it in this case. But I don't know for sure, so I wouldn't bet
There's a "<...> usb_dnl_dfu" message before the u-boot kicks in and flashall.bat/sh reflashes all the pieces starting from IFWI, which is what I think implements the DFU board-side. And the sequence above sort of confirms my understanding. rkd do I get it right here?