OneStepCheckout is a great extension for your desktop site, but
it’s not compatible with your mobile theme and not a good user
experience for mobile either. To disable it just for the mobile
theme, add this to your .htaccess file in your website root
directory. This way the default checkout is shown.

In your root Magento folder there is a htaccess. You must
change the code below;

## redirect for mobile user agents

#RewriteCond %{REQUEST_URI} !^/mobiledirectoryhere/.*$
#RewriteCond %{HTTP_USER_AGENT}
“android|blackberry|ipad|iphone|ipod|iemobile|opera
mobile|palmos|webos|googlebot-mobile” [NC] #RewriteRule ^(.*)$
/mobiledirectoryhere/ [L,R=302]

in;

## redirect for mobile user agents

#RewriteCond %{REQUEST_URI} !^/mobiledirectoryhere/.*$
RewriteCond %{HTTP_USER_AGENT}
“android|blackberry|ipad|iphone|ipod|iemobile|opera
mobile|palmos|webos|googlebot-mobile” [NC] RewriteRule
^onestepcheckout/*$ /checkout/onepage/ [R=301,L] #RewriteRule
^(.*)$ /mobiledirectoryhere/ [L,R=302]

Here you see the Pagayo mobile theme settings in Magento. This
has nothing to do with the problem above.