Determining where the extra information from squashfs comes from

Question

I extracted the root file system from an IoT device, and I was able to peruse it using unsquashfs. I then changed a single byte in a single file, and recompressed it again using mksquashfs. When I inspect the two files, the original and the one I created, the output from binwalk is identical, except for the size. The original had a size of 1038570 bytes while the one I created had a size of 1086112. I have no idea where the extra data came from. Are there any tools or methods for determining what the difference is?

Answer 1

So it turns out I was missing a flag while creating the squashed file system. When using the xz compressor method, you can specify another flag, -Xbcj, that further compresses optimized per architecture. Once I added this and chose arm as my architecture, the file size was the same