# File lib/ec2/right_ec2_instances.rb, line 370
    def modify_instance_attribute(instance_id, attribute, value)
      attribute = INSTANCE_ATTRIBUTE_MAPPING[attribute.to_s] || attribute.to_s
      params = { 'InstanceId' => instance_id,
                 'Attribute'  => attribute }
      case attribute
      when "blockDeviceMapping"
        params.merge!(amazonize_block_device_mappings(value))
      when "userData"
        params['Value'] = Base64.encode64(value).delete("\n")
      else
        params['Value'] = value
      end
      link = generate_request('ModifyInstanceAttribute', params)
      request_info(link, RightBoolResponseParser.new(:logger => @logger))
    rescue Exception
      on_exception
    end