Yes you can run a 4GB card, if it is sdhc you will need bootloader 5.5112 ,
Most SD cards 4GB and above are SDHC, although there are a few 4GB, non SDHC available. Any navcore from 8.300 with B/L 5.5015, will support these larger sdhc cards.
Truck navcore 8.395 has B/L 5.5120, so you will not have a problem with a SDHC card.
tendriver wrote:Most SD cards 4GB and above are SDHC, although there are a few 4GB, non SDHC available. Any navcore from 8.300 with B/L 5.5015, will support these larger sdhc cards.
The only reason i said 5.5112 is because "5.5112 - offers full support for SDHC on all Tomtom models