[Q] Change bootloader Prestigio pmp3670b

Hi guys.
Trying to hack my device and rewrite its bootloader to make a prototype for my project, but I'm new to this.

I already have root permission on ClockworkMod Android.
Initially I tried to reinstall OS to Android that I build from source code. But device hasn't got fastboot. So I decided to start from the bottom.

Current problem is that I have to locate UART on my device. Can't provide a photo of its board.
http:##s8.postimg.org#rqfzm4pdx#device.jpg

I read some articles about it and have prepared oscilograph and multimeter. But still, need some help.
Processor is AllWinner A13, have found its datasheet. UART RX and TX pins are 151 and 152, 125 and 124, 13 and 12, and I have no idea how to connect to it.

Could you give me some hints or useful links? Maybe some advice, please?
Thanks in advance.

Trying to analyze pins with mutimeter. Do I have to turn on the device?

E:V:A said:

You need the correct USB-to-serial cable, like those offered by FTDI R232Vxxx models.

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I've got this one too. I've borrowed it from someone, but I don't know how to use it yet.

E:V:A said:

But you have to know what voltage to use!

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I found these four pins strange (in attachment), and checked it with multimeter. Pins from top to bottom 1, 2, 3, 4.
1-2: 3.25V,
1-3: 3.25V,
1-4: 3.25V.

What can I do to be sure than these are right pins before I start soldering?

E:V:A said:

What's on the backside?

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Click to collapse

:laugh: