Command ntg2.5 freezing

[ckember]

Last year I had some issues with my command unit freezing and dying, which went away, this has started agin this week but with a slightly different fault mode. For the last two days on the A41 from Aylesbury to Bicester, I have noticed that the route option is greyed out, when I then cancel the route and try to then re-calculate the route the command can't route to my destination. Cancelling the route and trying again leads to the navi screen freezing, and I can't select any other function. Turning the unit off from the front button, rather than a fuse pull, for a few minutes, it sometimes works and sometimes not. The unit only works when the Merc logo is shown on boot up. It was updated to the latest firmware and maps this time last year, and checked by commando line in the summer. What surprises me as the fault appears at the same point on my morning journey, and never on the return home. I have seen reports that the gps antenna can cause this type of failure. Any suggestions to the cause please?