X-cart's cart.php file operates differently between the 4.1.x branches. The fix is simple though.

For issues with payment methods not showing up do the following

Open up cart.php

Find this code you inserted:

# BCSE Begin - Mobile Mod #
if ($isMobile){
func_display("customer/mobile_checkout.tpl", $smarty);
exit;
}
# BCSE End - Mobile Mod #


Change it to:

# BCSE Begin - Mobile Mod #
if ($isMobile){
$smarty->assign("payment_methods",$payment_methods);
func_display("customer/mobile_checkout.tpl", $smarty);
exit;
}
# BCSE End - Mobile Mod #

For cart looping issues at the payment method selection step:

Open up skin1/customer/mobile_checkout.tpl

Find:

{elseif $login && $smarty.get.paymentid eq ""}
<form action="cart.php?mode=checkout" method="post" name="cartform">


Change it to:

{elseif $login && $smarty.get.paymentid eq ""}
<form action="cart.php?mode=checkout" method="get" name="cartform">
]]>
The mobile code you insert for the mod needs to go before the following code when using checkout one:

if ($active_modules['Checkout_One'])
require $xcart_dir."/modules/Checkout_One/checkout_one_cart.php";
// End Checkout One // ]]> ]]> userAgent)) { $this->isMobile = false; } at the bottom of...]]>
Open init.php file and add this in:

if (preg_match('/ipad/i', $this->userAgent)) {
$this->isMobile = false;
}

at the bottom of the __construct() function]]>