diff --git a/mt7603/main.c b/mt7603/main.c
index 1d92b7ca..2605dca3 100644
--- a/mt7603/main.c
+++ b/mt7603/main.c
@@ -641,7 +641,7 @@ mt7603_set_coverage_class(struct ieee80211_hw *hw, s16 coverage_class)
 {
 	struct mt7603_dev *dev = hw->priv;
 
-	dev->coverage_class = coverage_class;
+	dev->coverage_class = max_t(s16, coverage_class, 0);
 	mt7603_mac_set_timing(dev);
 }