How to prefill address field forms? I've been using the Prepopulate module for a while, and it works really well. It can't prefill an addressfield type field, though.

How can I achieve this?
Add something like this to your hook_form_alter() or hook_form_FORM_ID_alter():

  $form['field_address'][LANGUAGE_NONE][0]['#address']['country'] = 'US';
  $form['field_address'][LANGUAGE_NONE][0]['#address']['locality'] = 'Livermore';
  $form['field_address'][LANGUAGE_NONE][0]['#address']['administrative_area'] = 'CA';
  $form['field_address'][LANGUAGE_NONE][0]['#address']['postal_code'] = '94551';