Read-only (“RO”) data to be permanently imprinted in storage cells of a memory array are written to the memory array. One or more over-stress conditions such as heat, over-voltage, over-current and/or mechanical stress are then applied to the memory array or to individual storage cells within the memory array. The over-stress condition(s) act upon one or more state-determining elements of the storage cells to imprint the RO data. The over-stress condition permanently alters a value of a state-determining property of the state-determining element without incapacitating normal operation of the storage cell. The altered value of the state-determining property biases the cell according to the state of the RO data bit. The bias is detectable in the cell read-out signal. A pre-written ferroelectric random-access memory (“FRAM”) array is baked. Baking traps electric dipoles oriented in a direction corresponding to a state of the pre-written data and forms am RO data imprint.