A method and an apparatus for establishing an operating environment by certifying a code image received from a host over a communication link are described. The code image may be digitally signed through a central authority server. Certification of the code image may be determined by a fingerprint embedded within a secure storage area such as a ROM (read only memory) of the portable device based on a public key certification process. A certified code image may be assigned a hash signature to be stored in a storage of the portable device. An operating environment of the portable device may be established after executing the certified code.