I used Binwalk to extract firmware files, extracted content include 2 folders and one binary file.


Squashfs-root contains file system, '_351C.extracted' folder contains security certificates (.crt). Don't know what is '351C' binary file (2.96 Mb).

Now I need to rebuild firmware back to binary image (.bin). How to rebuild this into binary firmware image? I tried use Firmware Mod Kit to extract fw, but it old, fails to run on my LTS 16.04 due missing some dependencies.

The FW file.

1 Answer 1


It really depends on the firmware format. If it was pure squashfs, without any additional header, just generate the new firmware file out of your set of files via mksquashfs https://elinux.org/Squash_FS_Howto#Creating_and_using_squashed_file_systems Otherwise, you'll need to append header/footer to the squashfs file to make it look like the original firmware.

  • For more specific, I added an actual FW file. Is there other tools or methods to add header and footer and rebuild to original binary?
    – Lexx Luxx
    Dec 21, 2017 at 14:57

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