Network is updating your prl
A Sprint user who desires to update his network settings can enhance the quality of his cell phone signal, lessen the number of calls he drops and experience fewer problems with his online connection.
But If I update the PRL by sending the ATD*228, it returns ACTIVATION: Success.
PRL updates are meant for CDMA networks, and both T-Mobile and AT&T utilize GSM networks.
If you are having problems while roaming, contact your carrier directly for assistance.
You can update the Preferred Roaming List on your Sprint i Phone by dialing ##873283# on your device.
A message will appear on the device that the process has started and you will received a notification once complete.