Thank you for the tip. It definitely seem relevant to this problem.
[Chris Hofstaedtler] > I imagine the kernel driver will request one of the > brcmfmac43456-sdio* files as included in raspi-firmware, but > also present in firmware-brcm80211. As far as I can tell, and <URL: https://bugs.debian.org/999485 > seem to indicate the same, these files are not yet present in firmware-brcm80211. -- Happy hacking Petter Reinholdtsen
