What's the difference between .img and .bin files for router firmwares?

Question

OpenWRT and DD-WRT for example supply two files:

• factory (.img)
• sysupgrade (.bin)

Why is one a .img and the other a .bin?

Does it matter which one I just and if yes, when should I choose which?

Solution

OpenWRT and DD-WRT are just two different projects that "power" routers. Look at it as if you're comparing Linux distributions. Your question would be similar to asking what the difference between Ubuntu and Fedora is. They offer different features for different purposes.

About the files: One is an .img file, which completely erases the firmware and replaces it with a new image. The .bin is just a "sysupgrade" so it's just an upgrade that doesn't replace the current image.

Comments

[studiohack]

nice answer! +1

[Georg Schölly]

So when do I have to use which? I tried upgrading through the web interface using a .img and it didn't work. Is this expected behaviour?

[Pylsa]

@Georg that depends on your needs, check out their respective websites for all features. As for updating, this will only work if you already have the custom firmware installed.

[Belmin Fernandez]

@BloodPhilia: Guessing with ".bin is just and "sysupgrade"" you meant to say ".bin is just a "sysupgrade"". Good analogy though. +1

[Gregory]

@GeorgSchölly according to GL.inet's documentation it's necessary to use .img files when you have a router that doesn't even boot due to a failed firmware installation. Some routers have Uboot which allows you to replace the firmware on your router and it requires to upload a .img file.