diff --git a/quirks/50-system-apple.quirks b/quirks/50-system-apple.quirks
index f643ccc6..9f6d172d 100644
--- a/quirks/50-system-apple.quirks
+++ b/quirks/50-system-apple.quirks
@@ -34,7 +34,7 @@ MatchProduct=0x030E
 AttrSizeHint=130x110
 AttrTouchSizeRange=20:10
 AttrPalmSizeThreshold=900
-AttrThumbSizeThreshold=800
+AttrThumbSizeThreshold=700
 
 [Apple Touchpad OneButton]
 MatchUdevType=touchpad
diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
index 64041752..53e3c22f 100644
--- a/src/evdev-mt-touchpad.c
+++ b/src/evdev-mt-touchpad.c
@@ -1133,16 +1133,17 @@ tp_thumb_detect(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time)
 	 * a thumb.
 	 */
 	if (tp->thumb.use_pressure &&
-	    t->pressure > tp->thumb.pressure_threshold)
+	    t->pressure > tp->thumb.pressure_threshold) {
 		t->thumb.state = THUMB_STATE_YES;
-	else if (tp->thumb.use_size &&
-		 (t->major > tp->thumb.size_threshold ||
-		  t->minor > tp->thumb.size_threshold))
+	} else if (tp->thumb.use_size &&
+		 (t->major > tp->thumb.size_threshold) &&
+		 (t->minor < (tp->thumb.size_threshold * 0.6))) {
 		t->thumb.state = THUMB_STATE_YES;
-	else if (t->point.y > tp->thumb.lower_thumb_line &&
+	} else if (t->point.y > tp->thumb.lower_thumb_line &&
 		 tp->scroll.method != LIBINPUT_CONFIG_SCROLL_EDGE &&
-		 t->thumb.first_touch_time + THUMB_MOVE_TIMEOUT < time)
+		 t->thumb.first_touch_time + THUMB_MOVE_TIMEOUT < time) {
 		t->thumb.state = THUMB_STATE_YES;
+	}
 
 	/* now what? we marked it as thumb, so:
 	 *