How to add item to cart programmatically, with attributes in Ubercart
Taking Chris's answer an putting it in Answer format for readability.

Figured it out, perhaps this will be of help for someone :)

$product_nid = 2;  
$some_data = array('attributes' =&gt; array( 
                   '1' =&gt; '1', 
                  ),
             );
uc_cart_empty(uc_cart_get_id());
$data = serialize($some_data);
uc_cart_add_item($product_nid, 
                 $qty = 1,
                 $data,
                 $cid = NULL,
                 $msg = TRUE,
                 $check_redirect = TRUE,
                 $rebuild = TRUE);