So i also have a 2010 IS250 no NAV, i have an itouch with OS4.0 and have experienced the Itouch connect play for a few seconds and then stop, i have seen a message on the Itouch saying the connected device is incompatible and i have seen the message on the radio show as error.
Yesterday while at the dealer the service guy told me there was nothing he could do - then the salesman connected his Iphone running OS4.1 and it worked without a hitch, as a work around i am using the Itouch through bluetooth.
The service manager also said they cant update firmware etc for these units - but i sure that must be incorrect.
