* @param start start byte address
* @param length number of bytes to unlock (must be a multiple of
* page size nand->writesize)
*
* @return 0 on success, -1 in case of error
*/
* @param start start byte address
* @param length number of bytes to unlock (must be a multiple of
* page size nand->writesize)
*
* @return 0 on success, -1 in case of error
*/