A technique for updating configurations of a target system in a computer. The method comprises booting, based on Preboot Execution Environment technology, a micro-system for updating configurations of a target system before booting the target system, the micro-system performing the steps of: (a) acquiring target configuration packages via a network from a server; (b) extracting target configuration data from said target configuration packages; and (c) updating the configurations of said target system by using said target configuration data, wherein said micro-system is independent of said target system.