The firmware knows that the largest file it can create under the "lowest" capable OS it supports is 4 GB and so it splits there. This is very common and not special or unique to DJIs implementation. FAT splits at 2 GB. (You can't format a SD card of capacity larger than 2 GB with FAT, must be FAT32). The Phantoms only support two formats, FAT32 and ExFAT.Let me be more clear. You can format the SD card FAT, FAT32 and exFAT. However, the _firmware_ only supports 4GB files. The _firmware_ is the limiting factor. Formatting has nothing to do with this. The firmware limits the file size to the lowest format possible which is FAT.
(I'm just learning "drone" but a 35 year IT guru)
This may be informative:
NTFS.com. NTFS vs FAT vs exFAT
Last edited: