2 files changed, 6 insertions, 3 deletions
diff --git a/actionmailer/lib/action_mailer/base.rb b/actionmailer/lib/action_mailer/base.rb
index 089b2ef0f6..699714c78f 100644
--- a/actionmailer/lib/action_mailer/base.rb
+++ b/actionmailer/lib/action_mailer/base.rb
@@ -225,6 +225,7 @@ module ActionMailer #:nodoc:
           end
           unless @parts.empty?
             @content_type = "multipart/alternative"
+            @charset = nil
             @parts = sort_parts(@parts, @implicit_parts_order)
           end
         end
diff --git a/actionmailer/lib/action_mailer/vendor/tmail/header.rb b/actionmailer/lib/action_mailer/vendor/tmail/header.rb
index 73639b5629..b4ef1809f0 100755
--- a/actionmailer/lib/action_mailer/vendor/tmail/header.rb
+++ b/actionmailer/lib/action_mailer/vendor/tmail/header.rb
@@ -754,9 +754,11 @@ module TMail
         strategy.meta @main
       end
       @params.each do |k,v|
-        strategy.meta ';'
-        strategy.space
-        strategy.kv_pair k, v
+        if v
+          strategy.meta ';'
+          strategy.space
+          strategy.kv_pair k, v
+        end
       end
     end