http://bugs.gentoo.org/485496

--- src/core/fat.cc
+++ src/core/fat.cc
@@ -82,4 +82,5 @@
 			uint8_t pmagic[2];
 		} __attribute__((__packed__)) fat32;
+		char sector[512];       // to make sure the whole struct is at least 512 bytes long 
 	} __attribute__((__packed__)) type;
 } __attribute__((__packed__));