Index: wp-admin/includes/class-wp-upgrader.php
===================================================================
--- wp-admin/includes/class-wp-upgrader.php	(revision 19518)
+++ wp-admin/includes/class-wp-upgrader.php	(working copy)
@@ -975,14 +975,14 @@
 		$working_dir = $this->unpack_package( $download );
 		if ( is_wp_error($working_dir) )
 			return $working_dir;
-
+/*
 		// Copy update-core.php from the new version into place.
 		if ( !$wp_filesystem->copy($working_dir . '/wordpress/wp-admin/includes/update-core.php', $wp_dir . 'wp-admin/includes/update-core.php', true) ) {
 			$wp_filesystem->delete($working_dir, true);
 			return new WP_Error('copy_failed', $this->strings['copy_failed']);
 		}
 		$wp_filesystem->chmod($wp_dir . 'wp-admin/includes/update-core.php', FS_CHMOD_FILE);
-
+*/
 		require(ABSPATH . 'wp-admin/includes/update-core.php');
 
 		return update_core($working_dir, $wp_dir);
Index: wp-admin/includes/update-core.php
===================================================================
--- wp-admin/includes/update-core.php	(revision 19518)
+++ wp-admin/includes/update-core.php	(working copy)
@@ -374,10 +374,11 @@
 	$maintenance_file = $to . '.maintenance';
 	$wp_filesystem->delete($maintenance_file);
 	$wp_filesystem->put_contents($maintenance_file, $maintenance_string, FS_CHMOD_FILE);
-
+	$result = true;
+/*
 	// Copy new versions of WP files into place.
 	$result = _copy_dir($from . $distro, $to, array('wp-content') );
-
+*/
 	// Custom Content Directory needs updating now.
 	// Copy Languages
 	if ( !is_wp_error($result) && $wp_filesystem->is_dir($from . $distro . 'wp-content/languages') ) {
@@ -465,6 +466,9 @@
 
 	// Remove maintenance file, we're done.
 	$wp_filesystem->delete($maintenance_file);
+
+	// If we made it this far:
+	do_action( '_core_updated_successfully', $wp_version );
 }
 
 /**
@@ -525,21 +529,28 @@
 /**
  * Redirect to the About WordPress page after a successful upgrade.
  *
- * This is a temporary function for the 3.3 upgrade only and will be removed in a later version.
- * 
+ * This function is only needed when the existing install is older than 3.3.0.
+ *
  * @since 3.3.0
  *
  */
-function _redirect_to_about_wordpress() {
-	// Only for WP version < 3.3.0
-	if ( version_compare( $GLOBALS['wp_version'], '3.3.0', '>' ) )
-		return;
-?>
+function _redirect_to_about_wordpress( $wp_version ) {
+	// Load the updated default text localization domain for new strings
+	load_default_textdomain();
+
+	// See do_core_upgrade()
+	show_message( __('WordPress updated successfully') );
+	show_message( '<span class="hide-if-no-js">' . sprintf( __( 'Welcome to WordPress %1$s. You will be redirected to the About WordPress screen. If not, click <a href="%s">here</a>.' ), $wp_version, esc_url( admin_url( 'about.php?updated' ) ) ) . '</span>' );
+	show_message( '<span class="hide-if-js">' . sprintf( __( 'Welcome to WordPress %1$s. <a href="%2$s">Learn more</a>.' ), $wp_version, esc_url( admin_url( 'about.php?updated' ) ) ) . '</span>' );
+	echo '</div>';
+	?>
 <script type="text/javascript">
-window.location = '<?php echo admin_url( 'about.php?upgraded' ); ?>';
+//window.location = '<?php echo admin_url( 'about.php?updated' ); ?>';
 </script>
-<?php
+	<?php
+
+	// Include admin-footer.php and exit
+	include(ABSPATH . 'wp-admin/admin-footer.php');
+	exit();
 }
-
-add_action( 'admin_footer-update-core.php', '_redirect_to_about_wordpress' );
-?>
+add_action( '_core_updated_successfully', '_redirect_to_about_wordpress' );
Index: wp-admin/update-core.php
===================================================================
--- wp-admin/update-core.php	(revision 19518)
+++ wp-admin/update-core.php	(working copy)
@@ -379,6 +379,7 @@
 		if ('up_to_date' != $result->get_error_code() )
 			show_message( __('Installation Failed') );
 	} else {
+		// Essentially, this code is forever dead.
 		show_message( __('WordPress updated successfully') );
 		show_message( '<a href="' . esc_url( self_admin_url() ) . '">' . __('Go to Dashboard') . '</a>' );
 	}
Index: wp-admin/about.php
===================================================================
--- wp-admin/about.php	(revision 19518)
+++ wp-admin/about.php	(working copy)
@@ -160,9 +160,16 @@
 </div>
 
 <div class="return-to-dashboard">
-	<?php if ( current_user_can( 'update_core' ) && isset( $_GET['upgraded'] ) ) : ?>
+	<?php
+	if ( current_user_can( 'update_core' ) && isset( $_GET['updated'] ) ) :
+		if ( is_multisite() ) : ?>
+	<a href="<?php echo esc_url( network_admin_url( 'update-core.php' ) ); ?>"><?php _e( 'Return to Updates' ); ?></a> |
+	<?php else : ?>
 	<a href="<?php echo esc_url( admin_url( 'update-core.php' ) ); ?>"><?php _e( 'Return to Dashboard &rarr; Updates' ); ?></a> |
-	<?php endif; ?>
+	<?php
+		endif;
+	endif;
+	?>
 	<a href="<?php echo esc_url( admin_url() ); ?>"><?php _e( 'Go to Dashboard &rarr; Home' ); ?></a>
 </div>