I have similar issues on my amd64 running -current.  I boot off a 64MB 
USB stick so that I can have root on Raidframe, and I'm usually greeted by:

uhub1: device problem, disabling port 2

on boot. "Sometimes" it actually works, and I see sd0 show up, but 
usually not.  There's no rhyme or reason that I can tell.

Anyhow, just a data-point that I'm seeing a similar issue on -current. 
Note that this isn't specific to umass; I see the same with a 
USB->Serial adapter I have as well.  This only seems to be an issue with 
devices present at boot, since the EHCI external drives I use for backup 
(and power on/connect only before a backup) always attach successfully.

	ScottE


Rhialto wrote:
> By accident I found out that my server can apparently boot from USB mass
> storage (in this case, an IDE disk in an external USB2 enclosure). The
> kernel (3.0/amd64) is loaded from the USB disk and starts. However, when
> it comes to using the root device, it claims a "port problem" and
> disables uhub4, which is the one that the drive is on. This is probably
> because the BIOS has tinkered with the USB controller already and NetBSD
> can't handle that.
> 
> Any chance that this is different/better in -current?
> 
> -Olaf.