Hi! My Tablet Zenithink C91 Upgrade finally is working with the Bluetooth and External GPS. First, you have to by a dongle that works on Zenithink C91 Upgrade with Android 4.0. I bought this one: bluetooth mini dongle USB 2,0 - R$ 4,87 Once you have the bluetooth dongle to work, just follow these steps: 1 - Install the aplication Bluetooth GPS 2 - Pairing with External Bluetooth GPS antenna (mine is Holux GPSlim 236) with the Zenithink C91 Upgrade (just do it once and it is) 3 - Open the aplication "Bluetooth GPS" we have installed, check "enable gps mock provide" (this part is very important) and give it to "connect" to your external Bluetooth GPS. 4 - Open your favorite browser and navigate... Working properly with Sygic, Ndrive, iGO.