Now I'm getting a little farther.
This is with the DeMuDi alsa-firmware package, which has the latest
version of the file in question.
To reiterate, this is what I've tried, in sequence:
$ sudo fxload -s ld2-ezusb.hex -I us122fw.ihx -D /proc/bus/usb/002/002
(Succeeds.)
$ sudo modprobe snd-usb-usx2y nrpacks=1
(Succeeds.)
If I specify a card for usx2yloader to load the firmware onto, it at
least tries, apparently. It still fails, though:
$ sudo usx2yloader -c 1
usx2yloader: error in loading
/usr/share/alsa/firmware/usx2yloader/us122.rbt
Is there some step I'm missing here, however obvious?
