CF Card or HDD DOS Format HowTo?

You can use "mkdosfs".

But there is a problem for large dos partition.

The "mkdosfs" builds all boot+fat image in memory before writing to disk, and there is no virtual memory in NIOS2 uclinux. So you will surely run out of memory to format a large disk using mkdosfs.

You may modify mkdosfs to write fat image directly to disk.