In a memory system including a host device and one or more nonvolatile memory devices, the host device reads, from a nonvolatile memory device connected in the system, a boot code used to operate a CPU of the host device before the CPU is activated. The boot code reading process is required to be performed with a simple method. A host device (2) transmits a first symbol including a synchronous code to a nonvolatile memory device (1). The nonvolatile memory device (1) receives the first symbol from the host device (2), and transmits a first symbol that is identical to the received first symbol to the host device (2), and then transmits a boot code to the host device (2). In this manner, the host device (2) reads a boot code from the nonvolatile memory device 1 with a simple method.