diff --git a/MC6809/test/Board.cpp b/MC6809/test/Board.cpp
index 8b8f50b..3b31044 100644
--- a/MC6809/test/Board.cpp
+++ b/MC6809/test/Board.cpp
@@ -4,7 +4,11 @@
 Board::Board(const Configuration& configuration)
 : m_configuration(configuration),
   m_cpu(EightBit::mc6809(*this)),
-  m_disassembler(m_cpu) {}
+  m_disassembler(m_cpu) {
+	std::vector<uint8_t> content(m_unused2000.size());
+	std::fill(content.begin(), content.end(), 0xff);
+	m_unused2000.load(content);
+}
 
 void Board::initialise() {
 
@@ -38,8 +42,11 @@ EightBit::MemoryMapping Board::mapping(uint16_t address) {
 	if (address < 0x8000)
 		return { m_ram, 0x0000, EightBit::MemoryMapping::ReadWrite };
 
+	if (address < 0xa000)
+		return { m_unused2000, 0x8000, EightBit::MemoryMapping::ReadOnly };
+
 	if (address < 0xc000)
-		return { m_io, 0x8000, EightBit::MemoryMapping::ReadWrite };
+		return { m_io, 0xa000, EightBit::MemoryMapping::ReadWrite };
 
 	return { m_rom, 0xc000, EightBit::MemoryMapping::ReadOnly };
 }
diff --git a/MC6809/test/Board.h b/MC6809/test/Board.h
index fef3a1f..a4ba56f 100644
--- a/MC6809/test/Board.h
+++ b/MC6809/test/Board.h
@@ -23,7 +23,7 @@ protected:
 private:
 	const Configuration& m_configuration;
 	EightBit::Ram m_ram = 0x8000;			// 0000 - 7FFF, 32K RAM
-											// 8000 - 9FFF, 8K unused
+	EightBit::Rom m_unused2000 = 0x2000;	// 8000 - 9FFF, 8K unused
 	EightBit::Ram m_io = 0x2000;			// A000 - BFFF, 8K serial interface, minimally decoded
 	EightBit::Rom m_rom = 0x4000;			// C000 - FFFF, 16K ROM