If your infotainment system is acting strangely, the problems that you are having are likely a result of poor connectivity between the infotainment system and the Sat NAV SD card. The system uses info from the SD card in the boot process and if that info gets corrupted the system becomes unstable or inoperative. Cold weather can exacerbate the issue.
The problem could simply be that the connections between the SD card and the card reader are marginal because of oxidation of the metal connections. Sometimes it works, sometimes not. Intermittent.
