USB connection unreliable while tethering

Device: Galaxy Nexus Android: CyangenMod 11.0 (Android 4.4.4) The IT department of my company doesn't support access of Mac devices to its network, but it does for Android devices. So I would like to connect my macbook (Mac OS X 10.9.4) to the internet by tethering my phone's Wi-Fi connection. Bluetooth tethering is reliable, but rather slow (max 200KB/s download speed, in reality it is rather something like 80KB/s). So, I tried to use the USB tethering with the help of HoRNDIS (release 5) , which is magnitudes faster (22MB/s) than Bluetooth tethering. However after a while (some minutes), the connection is lost. To restore it, I have to unplug the USB cable, plug it in again and retick the checkbox 'USB tethering' on the 'Tethering & portable hotspot' page in the 'Wireless & Network' settings. In order to solve this problem, I tried the following: - Enable 'Android debug mode' & 'ADB over Network' - Screen always on Unfortunately, these attempts didn't work. Does anyone have a similar problem or workaround?