diff --git a/mt7603.h b/mt7603.h
index d5f97ec6..344e559d 100644
--- a/mt7603.h
+++ b/mt7603.h
@@ -61,7 +61,7 @@ struct mt7603_mcu {
 };
 
 struct mt7603_dev {
-	struct mt76_dev mt76;
+	struct mt76_dev mt76; /* must be first */
 
 	struct mutex mutex;
 	struct cfg80211_chan_def chandef;
diff --git a/mt76x2.h b/mt76x2.h
index 992cf454..fdec5982 100644
--- a/mt76x2.h
+++ b/mt76x2.h
@@ -97,7 +97,7 @@ struct mt76x2_rate_power {
 };
 
 struct mt76x2_dev {
-	struct mt76_dev mt76;
+	struct mt76_dev mt76; /* must be first */
 
 	u8 macaddr[ETH_ALEN];
 	struct mac_address macaddr_list[8];