Bus 006 Device 008: ID 1a86:7523 QinHeng Electronics HL-340 USB-Serial adapter
[38197.600079] usb 6-2: new full-speed USB device number 2 using uhci_hcd[38197.798191] usb 6-2: New USB device found, idVendor=1a86, idProduct=7523, bcdDevice= 2.54[38197.798199] usb 6-2: New USB device strings: Mfr=0, Product=2, SerialNumber=0[38197.798204] usb 6-2: Product: USB2.0-Serial[38198.379254] usbcore: registered new interface driver usbserial_generic[38198.379744] usbserial: USB Serial support registered for generic[38198.381831] usbcore: registered new interface driver ch341[38198.381842] usbserial: USB Serial support registered for ch341-uart[38198.381864] ch341 6-2:1.0: ch341-uart converter detected[38198.387255] usb 6-2: ch341-uart converter now attached to ttyUSB0
Using Port : /dev/ttyUSB0 Using Programmer : arduino Overriding Baud Rate : 57600 AVR Part : ATmega328P Chip Erase delay : 9000 us[...]avrdude: Device signature = 0x1e950f (probably m328p)
Why would that be a problem ?Does it say on the PCB or on the site that you would get an original Arduino product ?If not, you should have expected a clone, and that is what you got.
Take another look at those pictures of yours.The same stuff obscuring the text, is all over the PCB.And it seems to be moving too.The dirt at pin 22 leads straight away from that pin in the 2nd picture, and makes a curve to pin 23 on the 3rd picture.