When I bought my Raspberry Pi I also ordered this tiny usb wifi adapter (TP-LINK TL-WN725N) in order to play with my raspi everywhere. I got this adapter because I read it worked out of the box, it was cheaper than others and it supported WiFi-N. As you may guess I am writing this post because the first advantage, the out of the box one, did not work for me.
I read some forums and it seemed that I had purchased a newer version of this adapter, the TL-WN725N v2. It needs a different driver, the Realtek 8188eu, which is not included by default in the Raspbian distributed by the official web site of Raspberry Pi. So, to sum up, I was able to find the driver source code and now I have a wireless raspi. If you have the same problem with this adapter, read the following lines to obtain directly the .ko object and you will be done. If you want you can download the driver source code (link at the end), compile and install it on your own.
To make it work just download the kernel object (.ko) file which is the compiled module driver for the kernel. I will be updating this section for different kernel versions.
For raspbian image: 2013-07-26-wheezy-raspbian.img
8188eu.ko (Compiled in 2013-08) (605 downloads) (Working in kernel Linux raspberrypi 3.6.11+ #474 PREEMPT)
For raspbian image: 2013-09-25-wheezy-raspbian.img
8188eu.ko (Compiled in 2013-10) (405 downloads) (Working in kernel Linux raspberrypi 3.6.11+ #538 PREEMPT)
For raspbian image: 2013-12-20-wheezy-raspbian.img & 2014-01-07-wheezy-raspbian.img
8188eu.ko & firmware (Compiled in 2014-01) (1489 downloads) (Working in kernel Linux raspberrypi 3.10.24+ #614 PREEMPT & 3.10.25+ #622 PREEMPT)
For raspbian image: 2014-06-20-wheezy-raspbian.img
8188eu.ko & firmware (Compiled in 2014-06) (470 downloads) (Working in kernel Linux raspberrypi 3.12.22+ #691 PREEMPT)
For raspbian image: 2014-09-09-wheezy-raspbian.img
8188eu.ko & firmware (Compiled in 2014-09) (407 downloads) (Working in kernel Linux raspberrypi 3.12.28+ #709 PREEMPT)
For raspbian image: 2014-12-24-wheezy-raspbian.img
8188eu.ko & firmware (Compiled in 2014-12) (903 downloads) (Working in kernel Linux raspberrypi 3.12.35+ #730 PREEMPT)
Place the .ko object in the following path:
In my case it is the following path:
Last version of the rtl8188eu driver includes a firmware file called rtl8188eufw.bin you have to place this file under:
Now execute the following commands
We are done. You should see now the new interface (wlan0 normally) when the device is connected.
Driver source code: https://github.com/lwfinger/rtl8188eu