Not included in my earlier posting -

An occasional variation on hanging during read from the umass flash
is this message:

sd0(umass0:0:0:0): generic HBA error
umass0: invalid CSW: sig 0x53555355 should be 0x53425355

Once I even saw this message immediately upon inserting the flash
device.

As earlier reported there are no problems using the same device and
controller with ehci disabled in userconf.

-Chap