[Help] Please identify the pins on my HK101 STB motherboard

[mr_maxking]

Hi, I have the HK101 TV Box with s905D soc created by Foxconn. Ths OS was android 7.1.2. Please identify the part A on the photo. The pins 1 to 5 that I tested are 0v, 3.3v, 3.3v, 3.3v, 0v. I have no idea what it is. I thought the part B was TTL port. I tested the pins 1 to 4: 0, 3.3, 2.9,0 and it should be Gnd, Vcc, TX, RX but I connected with PC no result displayed. Is it possible the kernel disable the serial console? I want to root the box & I get the OTA files. How can I flash the image on the box? The USB_Burning_Tool seemed no accept the OTA file. The OTA files I extracted was the following:

system.patch.dat
META-INF\com\android\metadata
META-INF\com\google\android\update-binary
META-INF\com\google\android\updater-script
boot.img
bootloader.img
dtb.img
file_contexts.bin
logo.img
recovery.img
system.new.dat
system.transfer.list
META-INF\com\android\otacert
META-INF\MANIFEST.MF
META-INF\CERT.SF
META-INF\CERT.RSA

Can I repack the file that used by USB_Burning_Tool? Thanks a lot.