diff --git a/lpc_aspeed.hpp b/lpc_aspeed.hpp
index d6a35af..53fe39b 100644
--- a/lpc_aspeed.hpp
+++ b/lpc_aspeed.hpp
@@ -16,12 +16,12 @@
 {
   public:
     static std::unique_ptr<HardwareMapperInterface>
-        createAspeedMapper(std::size_t regionSize);
+        createAspeedMapper(std::uint32_t regionAddress, std::size_t regionSize);
 
-    LpcMapperAspeed(std::size_t regionSize,
+    LpcMapperAspeed(std::uint32_t regionAddress, std::size_t regionSize,
                     const internal::Sys* sys = &internal::sys_impl) :
-        regionSize(regionSize),
-        sys(sys){};
+        regionAddress(regionAddress),
+        regionSize(regionSize), sys(sys){};
 
     std::pair<std::uint32_t, std::uint32_t>
         mapWindow(std::uint32_t address, std::uint32_t length) override;
@@ -30,6 +30,7 @@
 
   private:
     static const std::string lpcControlPath;
+    std::uint32_t regionAddress;
     std::size_t regionSize;
     const internal::Sys* sys;
 };