Unfortunately I read the warnings AFTER I tried to uninstall the German language pack on firmware 5.1.0. (Bad idea, I know...)

There were some displaying issues like empty boxes (Fonts configuration) and incomplete text messages (USB mode).
I donīt know how to downgrade or reinstall firmware, so I decided to follow the uninstall procedure mentioned on this site.
Now the German localization field is missing.
Is there any (easy) way to restore the missing files from firmware 5.1.0?