i had same problem .. in MKIII .. last week i update to v.18-2 without any issues then i update to v.23 after finish the system changed to default mode !! every things is shown except Navigation !! i tried to upgrade and downgrade but nothing happen when i put the CD in NAV !! and the light of NAV always Flashing with CD or without !! i try every things and tricks but nothing changed !!

i need your help .. please

some one told me the board is damaged and need new one !!! and another one told me just re-coding with dealer .