Does it help if you use this line in "static const struct snd_usb_implicit_fb_match capture_implicit_fb_quirks[] = {": IMPLICIT_FB_BOTH_DEV(0x0582, 0x0109, 0x05, 0x01), /* BOSS eBand JS-8 */ For it, I attempted using your specific 0x05 ASYNC OUT endpoint address this time. I may be wrong, but I think Takashi's current patches are reading endpoint addresses directly from the hardware, and if so your BOSS eBand JS-8 would work if that line does. Takashi would know best, though, so I'm bracing myself for any corrections.