diff --git a/mt76x02.h b/mt76x02.h
index ba4c14ee..57665516 100644
--- a/mt76x02.h
+++ b/mt76x02.h
@@ -116,7 +116,7 @@ struct mt76x02_dev {
 
 	bool no_2ghz;
 
-	u8 coverage_class;
+	s16 coverage_class;
 	u8 slottime;
 
 	struct mt76x02_dfs_pattern_detector dfs_pd;
diff --git a/mt76x02_util.c b/mt76x02_util.c
index f9dc3bc1..b20e3aab 100644
--- a/mt76x02_util.c
+++ b/mt76x02_util.c
@@ -544,7 +544,7 @@ void mt76x02_set_coverage_class(struct ieee80211_hw *hw,
 	struct mt76x02_dev *dev = hw->priv;
 
 	mutex_lock(&dev->mt76.mutex);
-	dev->coverage_class = coverage_class;
+	dev->coverage_class = max_t(s16, coverage_class, 0);
 	mt76x02_set_tx_ackto(dev);
 	mutex_unlock(&dev->mt76.mutex);
 }