--- a/browser/confvars.sh
+++ b/browser/confvars.sh
@@ -16,18 +16,16 @@ if test "$OS_ARCH" = "WINNT"; then
             "$MOZ_UPDATE_CHANNEL" = "aurora" -o \
             "$MOZ_UPDATE_CHANNEL" = "beta" -o \
             "$MOZ_UPDATE_CHANNEL" = "release"; then
       if ! test "$MOZ_DEBUG"; then
         MOZ_STUB_INSTALLER=1
       fi
     fi
   fi
-elif test "$OS_ARCH" = "Linux"; then
-  MOZ_VERIFY_MAR_SIGNATURE=1
 elif test "$OS_ARCH" = "Darwin"; then
   MOZ_VERIFY_MAR_SIGNATURE=1
 fi
 
 # Enable building ./signmar and running libmar signature tests
 MOZ_ENABLE_SIGNMAR=1
 
 MOZ_CHROME_FILE_FORMAT=omni

--- a/toolkit/mozapps/update/tests/unit_base_updater/xpcshell.ini
+++ b/toolkit/mozapps/update/tests/unit_base_updater/xpcshell.ini
@@ -14,19 +14,19 @@ skip-if = toolkit == 'android'
 [marSuccessComplete.js]
 [marSuccessPartial.js]
 [marFailurePartial.js]
 [marStageSuccessComplete.js]
 skip-if = toolkit == 'gonk'
 reason = bug 820380
 [marStageSuccessPartial.js]
 [marVersionDowngrade.js]
-skip-if = os != 'win' && os != 'mac' && os != 'linux'
+skip-if = os != 'win' && os != 'mac'
 [marWrongChannel.js]
-skip-if = os != 'win' && os != 'mac' && os != 'linux'
+skip-if = os != 'win' && os != 'mac'
 [marStageFailurePartial.js]
 [marCallbackAppSuccessComplete_win.js]
 skip-if = os != 'win'
 [marCallbackAppSuccessPartial_win.js]
 skip-if = os != 'win'
 [marCallbackAppStageSuccessComplete_win.js]
 skip-if = os != 'win'
 [marCallbackAppStageSuccessPartial_win.js]

--- a/toolkit/mozapps/update/updater/archivereader.cpp
+++ b/toolkit/mozapps/update/updater/archivereader.cpp
@@ -77,28 +77,29 @@ VerifyLoadedCert(MarFile *archive, const
 */
 int
 ArchiveReader::VerifySignature()
 {
   if (!mArchive) {
     return ARCHIVE_NOT_OPEN;
   }
 
-#ifdef MOZ_VERIFY_MAR_SIGNATURE
+#ifndef MOZ_VERIFY_MAR_SIGNATURE
+  return OK;
+#else
 #ifdef UPDATER_XPCSHELL_CERT
   int rv = VerifyLoadedCert(mArchive, xpcshellCertData);
 #else
   int rv = VerifyLoadedCert(mArchive, primaryCertData);
   if (rv != OK) {
     rv = VerifyLoadedCert(mArchive, secondaryCertData);
   }
 #endif
+  return rv;
 #endif
-
-  return rv;
 }
 
 /**
  * Verifies that the MAR file matches the current product, channel, and version
  * 
  * @param MARChannelID   The MAR channel name to use, only updates from MARs
  *                       with a matching MAR channel name will succeed.
  *                       If an empty string is passed, no check will be done