Techniques in electronic systems, such as in systems including a processing chip and one or more external memory chips, provide improvements in one or more of system security, performance, cost, and efficiency. The processing chip includes autonomous hardware that enables the processing chip, without a use of any CPUs, to form an association between itself and a particular flash chip. Prior to an initial operational use of the processing chip, the autonomous hardware is able to generate a key unique to the processing chip using a physically unclonable function, and then to form the association by encrypting a stream of data using the key and writing the encrypted result to the flash chip. For example, the stream of data comprises a bootloader and an operating system, and the processing chip is able to begin the initial operational use by securely booting using data copied from the flash chip.