I have an SMC 2102USB/ETH (USB to ethernet converter).  It works fine
in 1.5_ALPHA2:

kue0: SMC, Inc. EZ Connect USB/Ethernet Converter, rev 1.00/0.02, addr 7
kue0: cold boot, downloading firmware
kue0: Ethernet address 00:80:0f:8e:38:d4

But in a kernel built today (1.5F) the firmware download always fails:

kue0 at uhub1 port 3
kue0: SMC, Inc. EZ Connect USB/Ethernet Converter, rev 1.00/0.02, addr 6
kue0: cold boot, downloading firmware
kue0: failed to load code segment: IOERROR
kue0: loading firmware failed
kue0: at uhub1 port 3 (addr 6) disconnected
kue0 detached
uhub1: device problem, disabling port 

Nothing appears to have changed in dev/usb, so I'm at a bit of a
loss.  Any suggestions where to start looking ?

dme.