Not long ago, Debian has decided to change its policy regarding non-free firmware. I have blogged about this on
LinuxNews (you might need to translate it to DE). Without Debian
clearly announcing this, users of sid and testing need to apply a change to their Debian sources.list to be able to obtain firmware-updates in the future.
No matter if you have non-free and /or contrib in your sources already, please add
non-free-firmware
to /etc/apt/sources.list.d/debian.list as in
deb http://deb.debian.org/debian/ unstable main contrib non-free non-free-firmware
Then update and dist-upgrade and you might already have some firmware coming in.