diff --git a/bits/18_cfb.js b/bits/18_cfb.js
index 61b8b78..c82bd31 100644
--- a/bits/18_cfb.js
+++ b/bits/18_cfb.js
@@ -441,7 +441,7 @@ function sleuth_fat(idx/*:number*/, cnt/*:number*/, sectors/*:Array<RawBytes>*/,
 			if((q = __readInt32LE(sector,i*4)) === ENDOFCHAIN) break;
 			fat_addrs.push(q);
 		}
-		sleuth_fat(__readInt32LE(sector,ssz-4),cnt - 1, sectors, ssz, fat_addrs);
+		if(cnt >= 1) sleuth_fat(__readInt32LE(sector,ssz-4),cnt - 1, sectors, ssz, fat_addrs);
 	}
 }