diff --git a/stim/envi/bil.h b/stim/envi/bil.h
index 3a4c81a..b45dd30 100644
--- a/stim/envi/bil.h
+++ b/stim/envi/bil.h
@@ -231,15 +231,18 @@ public:
 	}
 
 	//given a Y, return ZX slice (transposed such that the spectrum is the leading dimension)
-	int read_plane_zx(T* p, size_t y){
-		T* temp = (T*) malloc(X() * Z() * sizeof(T));	//allocate space to store the temporary xz plane
-		binary<T>::read_plane_2(temp, y);					//load the plane from disk
+	bool read_plane_zx(T* p, size_t y){
+		T* temp = (T*) malloc(X() * Z() * sizeof(T));		//allocate space to store the temporary xz plane
+		if(!binary<T>::read_plane_2(temp, y))				//load the plane from disk
+			return false;
+
 		size_t z, x;
 		for(z = 0; z < Z(); z++){
 			for(x = 0; x <= z; x++){
 				p[x * Z() + z] = temp[z * X() + x];		//copy to the destination frame
 			}
 		}
+		return true;
 	}
 
 	//load a frame y into a pre-allocated double-precision array
--
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