Recently, I bought a BPI-R1, using the offical openwrt 4.0 image. The WAN and LAN are work well now. But the wifi is still unstable. I have used 2 5db antennas. It only get 70% signal in about 3m. The speed through samba less than 2 MByte/s. Sometimes the connect is off. I can seach the SSID, but can't be connected. Only restarting the device can make the connect back. I have searched this problem on the net and tried some methods, for example, adding "option noscan ‘1’",changing "HT20" to "HT40", setting the "11n" hwmode, setting txpower to 20, adding "option wpa_group_rekey '0'". The signal is still weak and the speed is still low. I inserted a USB wifi card in the USB port, using a RT5370 chip. It works well. The speed is more than 2MBytes/s and stable. I once want to change the driver according an article. But the openwrt have no 'make' application and can't download. Now, I am considering that maybe the chip RTL8192cu is too weak and should be changed to a better one. What should I do? Is there any other solution? By the way, the speed of LAN port through samba can exceed 20 MByte/s.