enable UART2 ttys1 on Legacy 3.4.112-sun7i

Dear all,
I need your help.
 
I've built a fresh pcDuino3 firmware:
Armbian 5.14 Pcduino3  -default - Debian 8 Jessie - CLI - Kernel 3.4.112
 
And now I'm trying to enable UARTs (2, 5 and 6).
I've edited script.bin and now I got 4 ttyS devices.
 
Could you please tell me how to "atctivate" those UARTs and which pins shoul I use.
 
I guess that
UART2 (ttyS1) uses D0 and D1 pins
UART5 (ttyS2) uses SPI0_CS and SPI0_CLK pins

UART6 (ttyS3) uses SPI0_MOSI and SPI0_MISO pins
 

Am I right ?
 
And how to enable ttySs?
I tried following for the UART2
 
echo 1 > /sys/class/gpio/export
echo 25 > /sys/class/gpio/export

I attached my fex. file and pcDuino3 schema

 
Unfortunately it does not help me.
 
Thank you in advance.