1. An electronic system, comprising; at least one control processor; and a portable data module which is operatively connected to be accessible to said control processor; said portable data module containing boot codes for at least two mutually incompatible architectures; said portable data module also containing a data structure which indicates which of said incompatible architectures require which of said boot codes; whereby said control processor can look at said data structure, at boot, and continue the boot process using whichever of said boot codes is required by said control processor's architecture.