Gps-speedsurfing
The last firmware update (V1.3 B1014a) had an issue when you filled the data logger and wrapped back to the start. A firmware issue prevented the data logger from being properly cleared afterwards, no matter what you tried. This has now been fixed in V1.3 B1123T.

Available for download from the usual place:
http://mtbest.net/setting-up-navi-GT31.htm
KA