Arduino Uno port not listed on RaspberryPi 3b


My Arduino Uno won't list in linux terminal with "ls /dev/tty*. I have an additional power source for more than enough power. If I "lsusb" I see it listed as Atmel Corp... Please help.

Okay so I managed to figure it out for one. I flashed a new Arduino-usbserial-atmega16u2-Uno-Rev3.hex to the broken UNO using FLIP. Then I loaded ArduinoISP on the good one, set it as programmer and burned the bootloader to the defective, voila and Bob's your uncle.

Now the second defective uno won't work doing the above steps. It will go into DFU and I can flash a new hex on it, and I can burn a bootloader to it as well. Port comes up fine and dandy. If I do a loop test and use serial monitor, it sends and receives the characters. But when when I try to upload sketches to it it bottoms out.

Any suggestions?