as Rob Landley pointed out, need to fix the 1 versus i typo in indexing
diff --git a/coreutils/comm.c b/coreutils/comm.c
index d3ca9c1..772dafc 100644
--- a/coreutils/comm.c
+++ b/coreutils/comm.c
@@ -71,7 +71,7 @@
 	int i;
 
 	for (i = 0; i < 2; ++i) {
-		streams[i] = ((infiles[i][0] == '=' && infiles[1][1]) ? stdin : bb_xfopen(infiles[i], "r"));
+		streams[i] = ((infiles[i][0] == '=' && infiles[i][1]) ? stdin : bb_xfopen(infiles[i], "r"));
 		fgets(thisline[i], LINE_LEN, streams[i]);
 	}