Down Load file from this link:
After download unzip the file you get two files first "upgrade.lgu" and second "synctool_log.txt"
paste both of files in a clean and formatted pen drive.
insert the pendrive in your MediaNav and allow the upgrade.and please wait till re-boot the system(it will take minimum 12 to 15 Min.)after re-boot upgrade will be continued....
after complete progress your version will be 8.0.5.
Special Note:if you removed the pendrive in mid of progress then your system goes dead.and kwidcarsolution store will not be responsible.