That's not quite true. One can format a 4GB SD card with FAT16. However, that requires the use of 64K clusters, so wasted space will be high. Old versions of DOS (inc. Win95, 98, Me) limited the cluster size to 32K. That's why they couldn't use greater than 2GB partitions.Originally Posted by itguy07
The biggest problem is that 4GB+ cards are not simple SD cards, they are SDHC. That means electrically they are different. Standard SD slots do not support 4GB cards, regardless of the format. The slot needs to be SDIO.