--- a/modules/libmar/tool/mar.c
+++ b/modules/libmar/tool/mar.c
@@ -112,33 +112,33 @@ static int mar_test(const char *path) {
   return 0;
 }
 
 int main(int argc, char **argv) {
   char *NSSConfigDir = NULL;
   const char *certNames[MAX_SIGNATURES];
   char *MARChannelID = MAR_CHANNEL_ID;
   char *productVersion = MOZ_APP_VERSION;
-  uint32_t i, k;
+  uint32_t k;
   int rv = -1;
   uint32_t certCount = 0;
   int32_t sigIndex = -1;
 
 #if !defined(NO_SIGN_VERIFY)
   uint32_t fileSizes[MAX_SIGNATURES];
-  uint8_t* certBuffers[MAX_SIGNATURES];
+  const uint8_t* certBuffers[MAX_SIGNATURES];
   char* DERFilePaths[MAX_SIGNATURES];
 #if (!defined(XP_WIN) && !defined(XP_MACOSX)) || defined(MAR_NSS)
   CERTCertificate* certs[MAX_SIGNATURES];
 #endif
 #endif
 
-  memset(certNames, 0, sizeof(certNames));
+  memset((void*)certNames, 0, sizeof(certNames));
 #if defined(XP_WIN) && !defined(MAR_NSS) && !defined(NO_SIGN_VERIFY)
-  memset(certBuffers, 0, sizeof(certBuffers));
+  memset((void*)certBuffers, 0, sizeof(certBuffers));
 #endif
 #if !defined(NO_SIGN_VERIFY) && ((!defined(MAR_NSS) && defined(XP_WIN)) || \
                                  defined(XP_MACOSX))
   memset(DERFilePaths, 0, sizeof(DERFilePaths));
   memset(fileSizes, 0, sizeof(fileSizes));
 #endif
 
   if (argc > 1 && 0 == strcmp(argv[1], "--version")) {
@@ -371,17 +371,17 @@ int main(int argc, char **argv) {
         mar_close(mar);
       } else {
         fprintf(stderr, "ERROR: Could not open MAR file.\n");
         rv = -1;
       }
     }
     for (k = 0; k < certCount; ++k) {
 #if (defined(XP_WIN) || defined(XP_MACOSX)) && !defined(MAR_NSS)
-      free(certBuffers[k]);
+      free((void*)certBuffers[k]);
 #else
       /* certBuffers[k] is owned by certs[k] so don't free it */
       CERT_DestroyCertificate(certs[k]);
 #endif
     }
     if (rv) {
       /* Determine if the source MAR file has the new fields for signing */
       int hasSignatureBlock;