Binwalk

Binwalk can identify, and optionally extract, files and data that have been embedded inside of other files. While its primary focus is firmware analysis, it supports a wide variety of file and data types. Through entropy analysis, it can even help identify unknown compression or encryption.

Good for:

• Carving filesystems, bootloaders, and kernels out of a firmware image.
• Extracting embedded files once a target's flash has been dumped.
• Using entropy analysis to spot compressed or encrypted regions.

Notes: Open source (GitHub). The current version is a rewrite in Rust; it is usually the first tool to reach for after dumping a device's firmware.