Hi!
If you follow these instruktions your unit Will be back in business.
http://europecaraudio.com/diy-tutorials/how-to-update-pioneer-avic-f700bt-f900bt-f70bt-f90bt-system-t35.html
Make sure the link to the maps is for software and not handheld.
Only problem sit hat I hav'nt got Danish voice so I am still looking for a solution for that. Have the TTS files but dont know Where/how to do with Them.
Hope you manage to get it back.