Cannot talk to any of the ports of iMX8

[jaux_al]

I am trying access the iMX8 over the console and when I connected the board to the host over UART cable, I saw 4 com ports.
Firstly, I'm not sure why am I seeing 4 and not just one 1.  

Secondly, I opened teraterm, set baud rate to 115200 but couldn't type anything in the serial session for any of the ports.

What could possibly be wrong?

[b36401]

Are you sure the processor boots some valid image?
Please note that the bootROM itself does not use UART for the diagnostic console.
So first it should get something like u-boot and then you will see the console.

Please refer to this article regarding to boot process:
https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/i-MX8-Boot-process-and-creating-a-bootab...

[jaux_al]

I am using the following to flash the image...

bunzip2 -dk -f core-image-minimal-imx8qxpmek.sdcard.bz2 
sudo dd if=core-image-minimal-imx8qxpmek.sdcard of=/dev/sdb bs=1M conv=fsync

 and i see the SD card has .dtf files as well as the image file. Shouldn't that be enough?