The Master Subsidy Lock, or MSL, is a code used on most Sprint phones and tablets. The code restricts devices from being used on other providers’ networks.
Being able to use the MSL code to unlock a device is useful when transferring the device to a new network or selling the phone to someone who may use a different service provider.
Sprint provides MSL codes for devices under the condition that the person requesting the code is a current or former Sprint customer and provided that several other circumstances are met. The Sprint account associated with the device must be in good standing with payments made current, a fulfilled service agreement, no write-off balances and no collection balances. Also, the device must not be reported lost or stolen.