сканирование Samsung SCX-4x21 в Gentoo

в sane 0.10 был добавлен модуль xerox_mfp для моего и подобных МФУ

http://bugs.gentoo.org/show_bug.cgi?id=139715#c23

я отредактировал xerox_mfp.conf

#Dell MFP Laser Printer 1815dn
usb 0x413c 0x5124

#Xerox Phaser 6110MFP
usb 0x0924 0x3d5d

#Samsung SCX-4200
usb 0x04e8 0x3419

на sane-find-scanner отзывается:
valdos-desk isida # sane-find-scanner

# sane-find-scanner will now attempt to detect your scanner. If the
# result is different from what you expected, first make sure your
# scanner is powered up and properly connected to your computer.

# No SCSI scanners found. If you expected something different, make sure that
# you have loaded a kernel SCSI driver for your SCSI adapter.

found USB scanner (vendor=0x04e8 [Samsung], product=0x3419 [SCX-4x21 Series]) at libusb:002:006
# Your USB scanner was (probably) detected. It may or may not be supported by
# SANE. Try scanimage -L and read the backend's manpage.

# Not checking for parallel port scanners.

# Most Scanners connected to the parallel port or other proprietary ports
# can't be detected by this program.
valdos-desk isida # _

на scanimage -L выдаёт

valdos-desk isida # scanimage -L
device `xerox_mfp:libusb:002:008' is a SAMSUNG ORION multi-function peripheral
valdos-desk isida #

на scanimage выдаёт:

valdos-desk isida # scanimage
scanimage: no SANE devices found
valdos-desk isida # _

после чего:

valdos-desk isida # scanimage -L

No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).
valdos-desk isida # _

куда копать?