Linux partition shows as FAT32
Problem: I used rEFIt and its “Partitioning Tool” to install Linux, but now the Linux partition is marked as FAT32 in the MBR partition table.
Solution: Re-run the “Partitioning Tool” in the rEFIt menu.
This can happen when you run the “Partitioning Tool” before you actually install Linux on the Linux partition. In the GPT table, the same partition type is used for Windows FAT, Windows NTFS, and all kinds of Linux file systems. The rEFIt Partitioning Tool tries to detect which file system is actually present in the partition so that it can assign the proper MBR partition type. However, if there is no file system present in the partiton, it falls back to FAT32.
Of course you can also fix this manually using Linux fdisk.