--- write       2023-02-10 12:55:08.718191588 +0000
+++ /etc/net/scripts/contrib/initconf   2023-02-10 14:47:42.520544225 +0000
@@ -89,7 +89,7 @@
                                        esac
                                fi
                                # many others try to look as ethernet, so let's filter by iface name...
-                               if [ "${iface//[0-9]*/}" = "eth" ]; then
+                               if [[ "$iface" =~ ^(en[a-z]|eth) ]]; then
                                        # find and use link-level address
                                        LLADDR=`$IP li sh dev $iface | fgrep 'link/ether' | sed 's/^ *link\/ether //' | cut --delimiter=' ' --fields=1`
                                        # ...and by valid MAC address