In this paper we discuss how to port the operating system vx works to a specific platform based on AEM 9201 architecture. we have solved some problems which area keys to the transplantation of this operating system. first we introduce how to debug the startup code by JTAG emulator and the debugger during the pre-boot time when the systems can not provide WDB tools. then we focus on the design of the startup code. after that we discuss how to deal with the interrupts and exceptions. then we research the influence of the MMU mapping if we want to start the operating system from the flash. at the end we talk about the serial driver and END driver needed by the minimal system. we wish it can provide some help for us to understand the mechanism of the operating system and can be a reference in engineering practice.