Hello,

You can customize a shopping cart controls to display breadcrumbs or buttons for going back through cart steps, but do it carefully and make a backup first. The controls are located in the \CMSModules\Ecommerce\Controls\ShoppingCart\ folder (especially ShoppingCart.ascx and its code-behind) and the clicking actions can only set required shopping cart step like this:

this.LoadStep(1); // where 1 is a shopping cart step order

Best regards,
Jan Hermann