Format USB Drive with FAT on Mac with different Allocation Unit Size

For example to format FAT32 with 64kb allocation unit size:

sudo newfs_msdos -F 32 -c 128 -v VOLUMEID /dev/yourdiskdevice

with 32kb allocation unit size should be use 64 cluster size:

sudo newfs_msdos -F 32 -c 64 -v VOLUMEID /dev/yourdiskdevice

You should be able to do this from a command line using the newfs_msdos command. For example:

#> newfs_msdos -F 32 -V somevolumename /dev/youdiskdevice

The command takes many arguments that you may want to explore.. -c cluster-size for example.

I am sure you could google around for newfs_msdos for some usage examples and also man newfs_msdos

Hope this helps!