Have you ever getting this error when trying to build your own OpenWrt firmware?
* opkg_install_cmd: Cannot install package luci-app-sqm. * satisfy_dependencies_for: Cannot satisfy the following dependencies for openvpn-openssl: * kernel (= 5.4.101-1-ff9d3bf167b1c614d295517a71109216)
I am no expert but from my guess, the builder is trying to use compiled system packages which you did earlier. Yes you read that right. OpenWrt builder takes a long time on its first run, but will be very quick after that. What happen is, it builds all system packages and store them for next usage.
Fortunately, the solution is very simple. Simply run
$ make clean
Then just rebuild.
You will be prompted with some options when you ran $ make to compile the code. Simply hit ENTER for all of them.