pycom-fwtool: unusable language/font

[Elizar]

Hi folks,
we are using pycom-fwtool since a while to successfully update our Gpys.

Today, however, when a run the tool (newest version) from a linux command line (platform openSUSE Linux 4.12.14-lp151.28.52-default x86_64) we get the following window:

... which is not very helpful (at least for me!).

Where does pycom-fwtool take the font/language information from? How can I change it?