I've used image builder to create a custom firmware. After installing it i update the lan ip to 192.168.10.1 what i want to happen is when i use the reset button is the keep the contents of /etc/config/network and NOT use the one form firmware default is this possible?
You can 'bake in' the desired default lan IP (and other parameters) into the custom image. But, assuming that you're using a device that has squashfs, the whole point of the reset is to clear the post-install configurations and restore it to what is in ROM (from the squashfs partition).
You could disable the reset button (this can be risky, though) if your goal is to prevent the system from resetting.
But I guess it would be better to understand what you want to happen when the reset is performed, since normally the whole intent is to reset the device to a known good default state.
Yeah i'm aware of the default ip that can be applied at build time but i want to be able to change it and when reset button is pressed everything gets reset other than /etc/config/network or it gets backed up/copied back.
It's not generally possible to do this.
You could attempt to re-write and replace the firstboot routine. but this would effectively be entirely custom to your usecase.
why not just create a hotplug button script to fire a uci-defaults script to do as you desire ... look here to get started --> Attach functions to a push button