Booting and configuring a subsystem securely from non-local storage

A machine-implemented method for operating a portable device, the method comprising:

• in response to a boot command, executing a read-only memory (ROM) boot loader from a secure ROM of a wireless communications processor, wherein the ROM boot loader initializes hardware associated with wireless communications processor of the portable device;
• establishing, by the ROM boot loader, a communication link with an application processor of the portable device over an internal bus that couples the wireless communications processor with the application processor;
• fetching, by the ROM boot loader, a boot code image from a non-volatile storage device over the communication link, wherein the non-volatile storage device is associated with and accessed by the application processor via a first operating system (OS) executed within a first random-access memory (RAM) associated with the application processor;
• authenticating, by the ROM boot loader, the boot code image;
• and
• upon having successfully authenticated the boot code image, the ROM boot loader launching the boot code mage into a second RAM associated with the wireless communications processor to establish a second OS for the wireless communications processor, wherein by accessing the non-volatile storage device associated with the application processor via the communications link over the internal bus, the wireless communications processor does not have to maintain a separate non-volatile storage device.

A machine-readable storage medium having instructions stored therein, which when executed by a machine, cause the machine to perform a method for operating a portable device, the method comprising:

• in response to a boot command, executing a read-only memory (ROM) boot loader from a secure ROM of a wireless communications processor, wherein the ROM boot loader initializes hardware associated with wireless communications processor of the portable device;
• establishing, by the ROM boot loader, a communication link with an application processor of the portable device over an internal bus that couples the wireless communications processor with the application processor;
• fetching, by the ROM boot loader, a boot code image from a non-volatile storage device over the communication link, wherein the non-volatile storage device is associated with and accessed by the application processor via a first operating system (OS) executed within a first random-access memory (RAM) associated with the application processor;
• authenticating, by the ROM boot loader, the boot code image;
• and
• upon having successfully authenticated the boot code image, the ROM boot loader launching the boot code mage into a second RAM associated with the wireless communications processor to establish a second OS for the wireless communications processor, wherein by accessing the non-volatile storage device associated with the application processor via the communications link over the internal bus, the wireless communications processor does not have to maintain a separate non-volatile storage device.

A machine-implemented method for operating a portable device, the method comprising:

• in response to a command to update a software component for the portable device, generating a session key;
• encrypting the session key using a storage key that is derived from a unique identifier (UID) uniquely identifying the portable device;
• generating a recovery blob having embedded therein the session key encrypted by the storage key;
• encrypting the session key using a public key of a public/private key pair;
• transmitting the recovery blob and the session key encrypted by the public key to an authorization server, wherein the authorization server is configured to recover the session key by decrypting the session key using a private key of the public/private key pair;
• in response to the software component and the recovery blob downloaded from a provisioning server, recovering the session key from the recovery blob by decrypting the recovery blob using the storage key, wherein the software component is encrypted by the session key which is received by the provisioning server from the authorization server;
• and
• recovering the software component by decrypting encrypted software component using the session key that is recovered from the recovery blob, wherein the software component is to be installed in the portable device.