My take on the TP-Link WR703N Antenna Mod

There is a lot of info online on this little WR703N router, and also some guides on how to add an external antenna (check here, and here, for instance).

So, i won’t going much details, but this was the process:

Performance was greatly improved! My goal was to connect this to a colinear 8dBi omnidirectional antenna for my 3G to Wifi gateway.

Thoughts on the Huawei CRC-9 Antenna connector

Quick post on Huawei CRC9 antenna jack.

This is a very small antenna connector found on some of Huawei’s 3G broadband modems.

The jack has a ground and two pads. They are NC (normally closed) meaning that when you attach an antenna they will open up and the RF circuit will feed the external antenna instead of the internal one.

I had to dig around a lot to find some info on this, and found a russian site with some info.

CRC-9 principle of operation. pin 1 is the antenna jack, pin 2 is the internal antenna.

Detail of the connector:

Pin 1 is the antenna jack, pin 2 is the internal antenna.

Why is this relevant? Because i didn’t had a CRC-9 pigtail around and had to solder coax directly to the board. Yes, it works. No i don’t recommend. This was hooked up to my DIY yagi antenna.

Huawei E3131 external antenna mod

Hacking MicroSD cards

You should read the latest on hacking MicroSD cards by Bunnie Studios (

Some points to consider:

  • Every card has a ARM microcontroller;
  • Flash is usually bad, but it doesn’t go to waste. a 16GB card with 80% bad flash can be sold as a 2GB one;
  • Remember number 1? It can allow arbitrary code execution.
MicroSD Card controller
MicroSD Card controller



Interested on reading more?

This is the whole write up – – and here’s the whole video. Enjoy!