See https://www.cbp.gov/document/directives/cbp-directive-no-3340-049b-border-search-electronic-devices?language_content_entity=en https://www.cbp.gov/document/

See https://www.cbp.gov/document/directives/cbp-directive-no-3340-049b-border-search-electronic-devices?language_content_entity=en https://www.cbp.gov/document/directives/cbp-directive-no-334... > The border search will include an examination of only the information that is resident upon the device and accessible through the device's operating system or through other software, tools, or applications. Officers may not intentionally use the device to access information that is solely stored remotely. To avoid retrieving or accessing information stored remotely and not otherwise present on the device, officers will either request that the traveler disable connectivity to any network ( e.g., by placing the device in airplane mode and disabling Bluetooth and Wi-Fi connections) or where warranted by national security, law enforcement, officer safety, or other operational considerations, officers will themselves disable network connectivity. Officers should also take care to ensure, throughout the course of a border search, that they do not take actions that would make any changes to the contents of the device. and > Passcodes or other means of access obtained during a border inspection will only be utilized to facilitate the inspection of devices and information subject to border search. Passcodes or other means of access may not be utilized to access information that is only stored remotely. Passcodes or other means of access should only be recorded by the officer in a temporary format and should not be uploaded into CBP systems. Passcodes or other means of access recorded by the officer will be deleted or destroyed when no longer needed to facilitate the search of a given device.