K3s change of cluster-cidr or service-cidr


i tried to change cluster-cidr and service-cidr failed with some network problems surrouning the setup of flannel.
There seams no solution so i looked into the code and found in pkg/util/net.go the method GetDefaultAddresses and the use of that method in ./pkg/agent/config/config.go or ./pkg/cli/server/server.go.
I don’t understand the code in total but the pkg/agent/config/config.go there is the default listenaddress just used with out a check if there is something set in the config:

        nodeConfig.AgentConfig.NodeIPs = nodeIPs
        listenAddress, _, _, err := util.GetDefaultAddresses(nodeIPs[0])
        if err != nil {
                return nil, errors.Wrap(err, "cannot configure IPv4/IPv6 node-ip")
        nodeConfig.AgentConfig.NodeIP = nodeIPs[0].String()
        nodeConfig.AgentConfig.ListenAddress = listenAddress
        nodeConfig.AgentConfig.NodeExternalIPs = nodeExternalIPs

that might be my reason why the cluster-cidr change won’t work.