I've been searching for a solution, but couldn't find it here or wherever. I don't know if it's exactly programming, as is about **arduino**, but here it goes.
I have a **FREEDUINO UNO** board (pretty similar to ARDUINO UNO, but from bq), which perfectly worked on **Arduino 1.6.5** two days ago, BUT today it doesn'. Apparently, the port is missing, the port itself was ***ttyACM0***, in /dev/. In fact I have no option of choosing a port available. I'm using Ubuntu 14.04.

I already tried:

* all searching methods in /dev/ of ***ttyACM0*** and ***ttyUSB0*** in the terminal, it's not there.
* group
* **dialout** (and permisses and all about this option, is done)
* lsusb
* reboot
* start from root
* unplug and plug, and plugging in different ports

I would appreciate every solution which doesn't implies "unistall and install the Arduino" "have another version" or even "another ubuntu", cause it worked fine, and it can verify code and all of that. Also my board blinks when connected so is not dead. I hardly think 16u2 is dead. 

Help please, and thank you!