×

Manufacturing mode for secure firmware using lock byte

  • US 9,627,081 B2
  • Filed: 10/05/2007
  • Issued: 04/18/2017
  • Est. Priority Date: 10/05/2007
  • Status: Active Grant
First Claim
Patent Images

1. A method for securing non-volatile memory comprising:

  • updating a signature byte, stored within a non-volatile memory, from a default value specifying a write-protected mode to an updated value specifying a write-enabled mode;

    after updating the signature byte from the default value to the updated value, determining that the signature byte is set to a value associated with the write-enabled mode;

    write-protecting at least one sector of the non-volatile memory if the signature byte is not set to the value associated with the the write-enabled mode;

    after updating the signature byte from the default value to the updated value, preventing an entire sector in which the signature byte resides from being set to a predefined sector value unless a replacement firmware identifier associated with a replacement firmware matches a required replacement firmware identifier;

    determining whether a reflash of the non-volatile memory is authorized by comparing the replacement firmware identifier against the required replacement firmware identifier and indicating that reflash of the non-volatile memory is authorized if the replacement firmware identifier matches the required replacement firmware identifier; and

    if the reflash of the non-volatile memory is authorized, write-enabling the non-volatile memory, reflashing the non-volatile memory, and setting the signature byte to a value different from the value associated with the the write-enabled mode.

View all claims
  • 6 Assignments
Timeline View
Assignment View
    ×
    ×