[OpenWrt Wiki] DFS
https://openwrt.org/docs/techref/dfs22.02.2021 · OpenWrt uses Open Source drivers which might be abandoned by manufactorer or no longer support some 5GHz operation due to regulatory changes. Original factory drivers can offer DFS when OpenWrt does not. There are different DFS schemes: DFS-FCC (USA), DFS-ETSI (Europe), DFS-JP (Japan). Try to use the non DFS channels if you have old hardware ...