Problems with connman and wifi


I try to use wifi on a Beaglebone Black with an Edimax EW-7811UN USB dongle. I started with the image bone-debian-8.5-console-armhf-2016-08-14-2gb.img and installed connman and firmware-realtek via apt. My goal is to get an access point automatically, when the BBB is booted.
I currently face the problem that the wifi dongle is not activated (led on dongle is off) after a reboot. A “connmanctl enable wifi” returns “Error wifi: Already enabled”. A “connmanctl disable wifi” and “connmanctl enable wifi” activates the wifi dongle (led is on). Instead of manually disabling and reenabling wifi I can also restart the connman daemon by “systemctl restart connman.service” to activate the wifi dongle.
Does anybody have any hint, why the dongle is not active after boot? I already had a similar setup several months ago without this problems, but based on a much older debian version.