Hi.
I've kinda figured it out. While in test mode i have noticed that my flash disk was full (16kb remaining) and therefore could not even copy greek language in the Lang Folder.
I went to the buildings and POIS folder and deleted some countries e.g. Bulgary and Romania (6MB space). Then copied greek language.
Afterwards i deleted gpspara0.bin, gpspara1.bin, gpspara2.bin, gpspara3.bin and BOOM!!!!
My avic unit went back to normal. All settings stored and greek language installed.
Your support is really appreciated.
Thank you very much!!!!