Whoo, this was hard. I was working on extracting firmware and other files from the SCH-i909 ROM build. However, instead of presenting me with lovely .img files, the .tar file only contained .rfs files. WTF?

Googling had no answer. I could NOT make an .rfs file. Until I discovered this tutorial on XDA.

According to the poster, it’s simple to mount .rfs files in Linux.

Step 1: Create a temporary directory.

mkdir temp

Step 2: Mount the .rfs file itself.

sudo mount -o loop <filename>.rfs temp/

Step 3: Profit.

I still haven’t managed out how to repackage these .rfs files, but that’s a post for the future. Stay tuned.

EDIT: I’m an idiot. How do I unmount the file?

sudo umount temp/