Meta Box values not saving

Completely frustrated at this point with meta boxes. Using the WP example in the codex to create a simple text input meta box on both the write post & write page and the issue is that no value is saved when updating!

I’ve completely gone primal, testing on a 2010 child theme with only a functions.php file with

/* Define the custom box */

// WP 3.0+
// add_action('add_meta_boxes', 'myplugin_add_custom_box');

// backwards compatible
add_action('admin_init', 'myplugin_add_custom_box', 1);

/* Do something with the data entered */
add_action('save_post', 'myplugin_save_postdata');

/* Adds a box to the main column on the Post and Page edit screens */
function myplugin_add_custom_box() {
    add_meta_box(
        'myplugin_sectionid',
        __( 'My Post Section Title', 'myplugin_textdomain' ),
        'myplugin_inner_custom_box',
        'post'
    );
    add_meta_box(
        'myplugin_sectionid',
        __( 'My Post Section Title', 'myplugin_textdomain' ),
        'myplugin_inner_custom_box',
        'page'
    );
}

/* Prints the box content */
function myplugin_inner_custom_box() {

  // Use nonce for verification
  wp_nonce_field( plugin_basename(__FILE__), 'myplugin_noncename' );

  // The actual fields for data entry
  echo '<label for="myplugin_new_field">';
       _e("Description for this field", 'myplugin_textdomain' );
  echo '</label> ';
  echo '<input type="text" id="myplugin_new_field" name="myplugin_new_field" value="whatever" size="25" />';
}

/* When the post is saved, saves our custom data */
function myplugin_save_postdata( $post_id ) {

  // verify this came from the our screen and with proper authorization,
  // because save_post can be triggered at other times

  if ( !wp_verify_nonce( $_POST['myplugin_noncename'], plugin_basename(__FILE__) ) )
      return $post_id;

  // verify if this is an auto save routine.
  // If it is our form has not been submitted, so we dont want to do anything
  if ( defined('DOING_AUTOSAVE') && DOING_AUTOSAVE )
      return $post_id;

  // Check permissions
  if ( 'page' == $_POST['post_type'] )
  {
    if ( !current_user_can( 'edit_page', $post_id ) )
        return $post_id;
  }
  else
  {
    if ( !current_user_can( 'edit_post', $post_id ) )
        return $post_id;
  }

  // OK, we're authenticated: we need to find and save the data

  $mydata = $_POST['myplugin_new_field'];

  // Do something with $mydata
  // probably using add_post_meta(), update_post_meta(), or
  // a custom table (see Further Reading section below)

   return $mydata;
}

Straight from the codex and the value doesn’t want to save… any suggestions?