Thanks for the reply
I was thinking about just replacing the CH340G chip.
Is there any firmware for this chip? This just a serial to USB converter right?? I've to buy one and replace it, right?
I've once replaced FT232 in TinyG and it worked.
About the blinking L led. It's only in the new board. My old board has Marlin running on it. In that if I press reset L led just turn ON and OFF; no continuous blinking
Can I just buy one chip and replace it?
And I need the USB communication part. It's not only about uploading the sketch, but also my 3D printer communicates to software using USB