Inside a internet radio firmware file I found a file system, and I don't know which one it is.

What I know:

  • (The first two bytes are 0A 4C (maybe magic byte))
    • they are actually not part of the file system data
  • Now 4 bytes with the length of the index
  • Entries in the index begin with a type of 1 byte:
    • type 00: File
      • 1 byte file name length
      • x bytes with the file name
      • 4 bytes file length
      • 4 bytes offset of the data in the file system
      • 4 bytes (unknown usage)
    • type 01: Folder
      • 1 byte folder name length
      • x bytes with the folder name (root folder name is 0 bytes)
      • 1 byte: number of entries/files in that folder

All offsets and lengths are little endian.

What file system could that be? I don't think that the developers built their own file system.

The firmware file is from http://update.wifiradiofrontier.com/Update.aspx?c=ir-mmi-FS2026-0500-0052&m=1122334455&v=2.6.17.EX53300-2RC3&t=Cust-File&n=2.11.12.EX65933-4RC2&f=/updates/ir-mmi-FS2026-0500-0052.2.11.12.EX65933-4RC2.isu.bin

binwalk does not detect the filesystem.

The file system I mean starts at 0x1dc1e6. I already wrote a working parser for that file system, but I'd like to know if that is a known fs type.

  • can you share the firmware file? Have you tried using binwalk to analyze the file?
    – julian
    May 21, 2019 at 14:21

1 Answer 1


It does not sound like a well-known file system. Probably it is just something custom the programmers came up with for this project.

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