When downloading a new ResinOS image preconfigured for your application, you have the “advanced” option to “Download configuration file only”.
I guess this option allow you to reuse a downloaded image for an other application without downloading again the full 1.8 Go (I know it’s compressed during download, but still).
Is there a doc somewhere on how to use this configuration file on an existing image ? Do you have to edit it (name and/or content) ? What would be the software to mount and edit the .img file without flashing it on a microSD card ?
burn your image, take the downloaded appnicationslug.config.json and replace the config.json on the SD card or USB stick that you’ve burned to (resin-boot partition). Just have to make sure that the image and the configuration are for the same device types.
burn your image, and run the resin-cli to inject the configuration: sudo resin config inject appnicationslug.config.json --type devicetype and it will prompt you for your SD card or USB stick path
you can modify the image to put the config.json there, replacing the one that it was downloaded with: take the image file and mount the resin-boot partition from there (recommend using kpartx -a resin-applicationslug-xyz.img), and copy the appnicationslug.config.json there over the config.json. Unmount and detach with kpartx -d ...., and then when you burn the file, you will get devices for that application.
How are these? And yeah, we’ll need to document more of the nitty-gritty of these advanced options and their usage.
Btw, the compressed image is on the order of ~140MB for the Pi for example, you can choose to download the .gz images for example to see that - it’s the same compression just explicitly. Or you can choose .zip compression there too.