// data-id-product instead of using rel tag

themes/default-bootstrap/mobile/product-desc-features.tpl

@@ -72,7 +72,20 @@
 								{assign var="btn_class" value="disabled"}
 								{capture assign="btn_more"}<span class="availability">{if (isset($accessory.quantity_all_versions) && $accessory.quantity_all_versions > 0)}{l s='Product available with different options'}{else}{if !$PS_CATALOG_MODE}{l s='Out of stock'}{/if}{/if}</span>{/capture}
 							{/if}
-							<a class="{$btn_class}" data-role="button" data-inline="true" data-theme="e" data-icon="plus" data-mini="true" class="exclusive button ajax_add_to_cart_button" href="{$btn_href}" rel="ajax_id_product_{$accessory.id_product|intval}" title="{l s='Add to cart'}" data-ajax="false">{l s='Add to cart'}</a>
+							<a 
+								class="{$btn_class}"
+								data-role="button"
+								data-inline="true"
+								data-theme="e"
+								data-icon="plus"
+								data-mini="true"
+								class="exclusive button ajax_add_to_cart_button"
+								href="{$btn_href}"
+								data-id-product="{$accessory.id_product|intval}"
+								title="{l s='Add to cart'}"
+								data-ajax="false">
+								{l s='Add to cart'}
+							</a>
 							{$btn_more}
 						</div><!-- .btn-row -->
 					</li>