Do I really have to redownload my balena images to change Wifi/Application?

I’m finding myself redownloading 130+MB BalenaOS images from the dashboard all the time for my applications.

Does the CLI not allow me to have a single base Balena image of 130MB and change details such as what application to use and the ssid?

Yes, you can download the config.json

The config.json is in the /boot part of the image or the part that mounts when you are using an SD card and windows.

The config.json contains details like what application to join, the frist set of wifi creds, and other stuff.

If you have all the same type of devices, you should be able to provision a device with a master image of the right version for the device and swap in the right config.json for what application you want it to join.

Personally speaking, we use a sd card cloning service. The master I gave them was for a staging application where we name devices as we plug them in there and then move them to their final home. This flow could be improved but works for us.

I can’t give you details on how to pull config.json’s from the cli, but in the dashboard it is just another button.

But it looks like they have documentation on editing from the cli here.


Actually, wifi configuration is no longer managed by the config.json file. Network connections are configured using NetworkManager configuration files. You can check this documentation

Such files can be edited in the downloaded image before you flash it.

To facilitate the process, we also have command line tools that allow to pre-configure the image before flashing the OS (see balena os configure).