After updating my 830 to FW 5.0, french is not available in the language list.
When updating, I was on english (due to several bad french translations in FW 4.10 who bothered me !).
Is it due to this setting, I don't know ? But do you think that there is different 5.0 FW containing different list of languages ?
Main question, how to reinstall it with the correct FW ?