Re: Troubles booting Pi2 from USB using bootcode.bin method

From: bob prohaska <fbsd_at_www.zefox.net>
Date: Sat, 30 Oct 2021 21:35:53 UTC
On Sat, Oct 30, 2021 at 01:41:52AM -0700, Mark Millard via freebsd-arm wrote:
> >> 
> >> Yep: it picks one. Swapping or moving which ports are used
> >> may change which one is used when both are connected.
> >>

It appears that choice of USB hub ports makes a difference. 
At least sometimes, connecting the USB3 drive to the hub
port formerly occupied by the USB2 drive results in a hands-
off boot. Unfortunately, not always. Interrupting u-boot
and issuing a usb reset command or two generally finds the
USB3 drive, which can then be booted explicitly.



I've captured one failure session at
http://www.zefox.net/~fbsd/rpi2/bootproblems/bootlog-usb3-solo.fail
but cannot reliably reproduce it. 

When the console offers the
U-Boot> 
prompt, is that coming from bootcode.bin, or something else?

Could anything be learned from trying to boot the armv7-configured
disk on a Pi3B or B+ ? That's a relatively easy experiment.  I'm
trying to use a rather old Pi with a comparatively new USB drive.
The Pi3s on hand are at least somewhat more modern.

Thanks for reading,

bob prohaska