Firmware files come in various formats, often specific to the platform, architecture, or device being updated. These file extensions are used to package and distribute firmware updates. Below is a list of common firmware file extensions and their typical use cases:
Common Firmware File Extensions
| Extension | Description | Example Use Case |
|---|---|---|
| .bin | Binary file, often a raw, uncompressed firmware image. | Used in embedded systems, microcontrollers, and IoT devices. |
| .hex | Intel HEX format, stores firmware in ASCII-encoded hexadecimal format. | Popular in microcontrollers (e.g., PIC, AVR). |
| .elf | Executable and Linkable Format, contains both code and debug information. | Debugging and testing on embedded platforms. |
| .img | Image file, sometimes used for bootloaders or full system images. | Bootloaders or OS images for embedded systems. |
| .dfu | Device Firmware Update file, a standard format for USB firmware updates. | USB devices (e.g., keyboards, printers). |
| .upd | General update file, sometimes used for proprietary firmware updates. | Consumer electronics (e.g., TVs, routers). |
| .rom | ROM image file, used for firmware stored in read-only memory. | BIOS or UEFI firmware updates for PCs. |
| .iso | ISO disk image, occasionally used for firmware distribution with bootable updates. | Firmware updates for systems like servers or appliances. |
| .scap | System firmware capsule file, often used in UEFI firmware updates. | BIOS/UEFI firmware updates. |
| .bin.sig | Signed binary file, includes a cryptographic signature to ensure authenticity. | Secure firmware updates. |
| .prg | Program file, sometimes used for older embedded systems or game consoles. | Legacy firmware updates. |
| .srec / .s19 | Motorola S-Record format, stores firmware in ASCII text with checksum information. | Used in embedded systems for error-resilient updates. |
| .tar / .tgz | Compressed archive, often containing firmware and supporting files. | Linux-based systems (e.g., routers, NAS devices). |
| .fw | Generic firmware extension, used for custom or proprietary firmware. | IoT or industrial devices. |
| .vme | Firmware file for VxWorks-based systems. | Industrial control systems and aerospace devices. |
| .dmg | macOS disk image, occasionally used for firmware updates. | Apple devices (e.g., MacBooks). |
| .pkg | Package file, contains firmware and metadata. | Used in routers, modems, or set-top boxes. |
| .upd / .update | Generic update file for firmware updates. | Used in TVs, cameras, and other consumer electronics. |
| .exe | Executable firmware update, usually for Windows-based systems. | PC BIOS/UEFI firmware or peripheral updates. |
| .sys | System file, sometimes used as a firmware component. | Drivers and low-level system components in Windows. |
Specialized Firmware File Extensions
- .psw: Firmware for programmable power supplies.
- .nsu: Firmware update files for Nokia or other network devices.
- .eif: Encrypted firmware files for secure systems.
- .rmt: Remote management firmware or update files.
- .lzma: Compressed firmware using the LZMA algorithm.
- .uboot: Bootloader image for U-Boot-based embedded systems.
Understanding Firmware Extensions
- Proprietary Formats: Many manufacturers use custom extensions and encryption to secure firmware updates.
- Multi-Part Updates: Some systems split firmware into multiple components (e.g., bootloader, OS, and application firmware).