3027 installgrub can segfault when encountering bogus data on disk

@@ -44,11 +44,11 @@
         uint32_t        size;
         uint32_t        checksum;
 } bb_header_ext_t;
 
 uint32_t compute_checksum(char *, uint32_t);
-bblk_einfo_t *find_einfo(char *);
+bblk_einfo_t *find_einfo(char *, uint32_t);
 int find_multiboot(char *, uint32_t, uint32_t *);
 void add_einfo(char *, char *, bblk_hs_t *, uint32_t);
 int compare_bootblocks(char *, char *, char **);
 
 #ifdef  __cplusplus