Same problem on Lubuntu 18.04 with the build from the most current ubuntu repo (1.0.5 I believe. 2:1.0.5+dfsg2-4.1). The 1.8.4 version from the arduino website works fine.
Same problem on Lubuntu 18.04 with the build from the most current ubuntu repo (1.0.5 I believe. 2:1.0.5+dfsg2-4.1). The 1.8.4 version from the arduino website works fine.