Hi
I have a Route10 which is using Openwrt and the Linux kernel which have a GPL License.
Under the GPL License you have to provide the source code for any derivative work (such as a modifed kernel or openwrt build scripts) or links to the source code of non-modified components.
Extract from:
https://forum.archive.openwrt.org/viewtopic.php?id=68683
OpenWrt buildroot and the OpenWrt scripts are [licensed under the GPL]. When you distribute a binary image, OpenWrt’s GPLv2 License compells you to release the “scripts used to control compilation and installation of the executable”.
If you have not modified the actual source code, providing a link to the github source is fine, but you should still release your scripts used to control the compilation and installation. At minimum, this would be the config file if everything else remains standard.
GPL v2
https://www.gnu.org/licenses/old-licenses/gpl-2.0.en.html