Please learn to read error messages. You error is a missing firmware. You most likely installed the backports for nothing.
You have 2 occurrences of the following message:
[code]
[41731.112528] usb 2-2: ath9k_htc: Firmware - htc_9271.fw download failed...
You have 2 occurrences of the following message:
[code]
[41731.112528] usb 2-2: ath9k_htc: Firmware - htc_9271.fw download failed...