diff --git a/CHANGELOG.md b/CHANGELOG.md
new file mode 100644
index 0000000..59a0100
--- /dev/null
+++ b/CHANGELOG.md
@@ -0,0 +1,5 @@
+# Change Log
+## 0.1.1 (2023/03/27)
+- Fixed bug reading MEM2
+## 0.1.0 (2023/03/09)
+- Implemented WebSocket server
diff --git a/setup.cfg b/setup.cfg
index 066d579..c5275cd 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -1,6 +1,6 @@
 [metadata]
 name = supDolphinWS-server
-version = 0.1.0
+version = 0.1.1
 author = sup39
 author_email = sms@sup39.dev
 description = A WebSocket server for accessing memory of emulated games in Dolphin
diff --git a/src/supDolphinWS/server/dolphin.py b/src/supDolphinWS/server/dolphin.py
index a54bb5d..63974c1 100644
--- a/src/supDolphinWS/server/dolphin.py
+++ b/src/supDolphinWS/server/dolphin.py
@@ -46,24 +46,26 @@ class Dolphin():
       self.m = None
   def _read_bytes(self, addr, size):
     '''
-      addr: int
+      addr: int|None
       size: int
     '''
+    if addr is None: return None
     if MEM1_START <= addr <= MEM1_END-size:
       idx = addr-MEM1_START
-    elif MEM2_START <= addr <= MEM2_END-size and len(self.m) > MEM2_OFFSET:
+    elif MEM2_START <= addr <= MEM2_END-size and len(self.m.buf) > MEM2_OFFSET:
       idx = MEM2_OFFSET + addr-MEM2_START
     else: return None
     return self.m.buf[idx:idx+size].tobytes()
   def _write_bytes(self, addr, payload):
     '''
-      addr: int
+      addr: int|None
       payload: bytes
     '''
+    if addr is None: return None
     size = len(payload)
     if MEM1_START <= addr <= MEM1_END-size:
       idx = addr-MEM1_START
-    elif MEM2_START <= addr <= MEM2_END-size and len(self.m) > MEM2_OFFSET:
+    elif MEM2_START <= addr <= MEM2_END-size and len(self.m.buf) > MEM2_OFFSET:
       idx = MEM2_OFFSET + addr-MEM2_START
     else: return None
     self.m.buf[idx:idx+size] = payload