On Mon, Nov 17 2014, Lele Gaifax wrote:
>> Could you try this patch please?
>> 
>> diff --git a/emacs/notmuch-show.el b/emacs/notmuch-show.el
>> index 6e03f1e..1592ca9 100644
>> --- a/emacs/notmuch-show.el
>> +++ b/emacs/notmuch-show.el
>> @@ -235,9 +235,9 @@ For example, if you wanted to remove an \"unread\" tag and add a
>>         (let ((buf (generate-new-buffer (concat "*notmuch-msg-" id "*"))))
>>           (with-current-buffer buf
>>  	   (let ((coding-system-for-read 'no-conversion))
>> -	     (call-process notmuch-command nil t nil "show" "--format=raw" id)
>> -	     ,@body)
>> -	   (kill-buffer buf))))))
>> +	     (call-process notmuch-command nil t nil "show" "--format=raw" id))
>> +	   ,@body)
>> +	 (kill-buffer buf)))))
>>  
>>  (defun notmuch-show-turn-on-visual-line-mode ()
>>    "Enable Visual Line mode."
>
> Yes! This works great, with it the forward buffer contains the signature
> loaded with the correct encoding, and the sendmail succeeds without
> prompting about unreadable chars.

That's good, thanks for testing. I'll work up and submit a proper patch.