is there any way to load MLO and u-boot directly from an USB device? I have found
different answers searching the net. One people say, the boot order can
be USB => UART => MMC => NAND (if user button is pressed or
resistors installed), others say, the ROM does not support USB boot.
What we want to do is a fallback boot. First, the board should try
from boot device A and if this fails due to to a hardware error, it should
try booting from an alternative device.
What we not want to do is to boot MLO/u-boot from eMMC and later
load linux from USB. This way is easy and works, but it is not a
fallback solution.
The boot order those people are talking about is probably OS only, and if not they’re not talking about this hardware. You have to at minimum boot MLO from flash media, or maybe serial. You can not load this from USB period.
Someone was working on “booting” over USB tether to an Android phone for GSoC a few years back. As far as I know the project was never really finished. No idea what Gerald is talking about there.
Ah, ok yeah that is what I was talking about. Seems to be finished now, and I have no interest in trying to make that work. For starters though, having to press the boot switch is a serious detraction.
“debian and ubuntu will use tarball from armhf.com website”
For me this is another detraction.
Aside from those two reason, the project is “fringe”, requires a specially compiled kernel. That adds a lot of stuff I’m not sure I’d want in a “production” image. For me, it’s just not necessary.