Hi Samer:
I updated to 2.1.5 via USB updater GUI software, so the USB part of the board is work, it can detect the board and update the firmware.
Also when I turn it on, I see top row are blocks, after a few seconds, the backlight is off (or dimmed), if I press any of the buttons (B1, B2, B3), LCD backlight will go back ON again, so PA port (at least PA0, PA1 and PA2 are working).
Since CH340 is working (I can update the firmware via GUI updater software), so TXD and RXD is working, which means PD0 and PD1 are working.
Also, ISP and network are working, which means PB7, PB6, PB5, PB4 are working.
None of above (CH340, network, ISP) use port C, so could port C being bad? Also PC1 and PC0 connects to EEPROM 24AA02E, so could 24AA02E gone bad?