Atheros AR9001U

Hello.
I'm having issues with my wireless usb stick. The model is supposed to be supportet, but breaks communication evry 10-20 min.
lsusb says about the stick:
 Bus 001 Device 007: ID 057c:8401 AVM GmbH Fritz!WLAN N [Atheros AR9001U]
The stick supports 11abgn networks. in 2.4 and 5 GHz range.
I'm using kernel 3.13.0-34-generic.

At the time I was using the built in version of carl.

Aug 23 20:02:43 uk-pc kernel: [ 4889.891261] usbcore: registered new interface driver carl9170
Aug 23 20:02:43 uk-pc kernel: [ 4889.895369] usb 1-4: driver   API: 1.9.7 2012-12-15 [1-1]
Aug 23 20:02:43 uk-pc kernel: [ 4889.895376] usb 1-4: firmware API: 1.9.6 2012-07-07

I updated manually to carl9170-1.fw-1.9.9 (I simply renamed the old fw and copyed the new one to /lib/firmware/carl9170-1.fw

The Syslog says about the crash:
Aug 23 20:23:37 uk-pc kernel: [ 6144.616517] usb 1-4: restart device (4)
Aug 23 20:23:39 uk-pc kernel: [ 6145.820619] usb 1-4: firmware upload failed (-110).
Aug 23 20:23:39 uk-pc kernel: [ 6145.821320] usb 1-4: Failed to restart device (-110).
Aug 23 20:23:39 uk-pc kernel: [ 6145.828552] ieee80211 phy1: writing reg 0x1c36f0 (val 0x2400) failed (-5)
Aug 23 20:23:39 uk-pc kernel: [ 6145.828561] ieee80211 phy1: writing reg 0x1c36f0 (val 0x2400) failed (-5)
Aug 23 20:23:39 uk-pc kernel: [ 6145.828568] ieee80211 phy1: writing reg 0x1c36f0 (val 0x2400) failed (-5)
Aug 23 20:23:39 uk-pc kernel: [ 6145.828575] ieee80211 phy1: writing reg 0x1c36f0 (val 0x2400) failed (-5)
Aug 23 20:23:39 uk-pc kernel: [ 6145.828582] ieee80211 phy1: writing reg 0x1c36f0 (val 0x2400) failed (-5)
Aug 23 20:23:39 uk-pc kernel: [ 6145.828588] ieee80211 phy1: writing reg 0x1c36f0 (val 0x2400) failed (-5)
Aug 23 20:23:39 uk-pc kernel: [ 6145.828594] ieee80211 phy1: writing reg 0x1c36f0 (val 0x2400) failed (-5)
Aug 23 20:23:39 uk-pc kernel: [ 6145.828601] ieee80211 phy1: writing reg 0x1c36f0 (val 0x2400) failed (-5)
Aug 23 20:23:39 uk-pc kernel: [ 6145.828607] ieee80211 phy1: writing reg 0x1c36f0 (val 0x2400) failed (-5)

Is there someone out there who can help me?
Regards,
Matthias