diff --git a/micropython/bluetooth/aioble-server/manifest.py b/micropython/bluetooth/aioble-server/manifest.py
index 0fb1840..c5b12ff 100644
--- a/micropython/bluetooth/aioble-server/manifest.py
+++ b/micropython/bluetooth/aioble-server/manifest.py
@@ -1,4 +1,4 @@
-metadata(version="0.4.0")
+metadata(version="0.4.1")
 
 require("aioble-core")
 
diff --git a/micropython/bluetooth/aioble/aioble/server.py b/micropython/bluetooth/aioble/aioble/server.py
index ed3299d..403700c 100644
--- a/micropython/bluetooth/aioble/aioble/server.py
+++ b/micropython/bluetooth/aioble/aioble/server.py
@@ -290,8 +290,8 @@ class Characteristic(BaseCharacteristic):
 
 
 class BufferedCharacteristic(Characteristic):
-    def __init__(self, service, uuid, max_len=20, append=False):
-        super().__init__(service, uuid, read=True)
+    def __init__(self, *args, max_len=20, append=False, **kwargs):
+        super().__init__(*args, **kwargs)
         self._max_len = max_len
         self._append = append
 
diff --git a/micropython/bluetooth/aioble/manifest.py b/micropython/bluetooth/aioble/manifest.py
index 24187af..2979a72 100644
--- a/micropython/bluetooth/aioble/manifest.py
+++ b/micropython/bluetooth/aioble/manifest.py
@@ -3,7 +3,7 @@
 # code. This allows (for development purposes) all the files to live in the
 # one directory.
 
-metadata(version="0.4.0")
+metadata(version="0.4.1")
 
 # Default installation gives you everything. Install the individual
 # components (or a combination of them) if you want a more minimal install.
diff --git a/micropython/bluetooth/aioble/multitests/ble_buffered_characteristic.py b/micropython/bluetooth/aioble/multitests/ble_buffered_characteristic.py
new file mode 100644
index 0000000..18ce7da
--- /dev/null
+++ b/micropython/bluetooth/aioble/multitests/ble_buffered_characteristic.py
@@ -0,0 +1,139 @@
+# Test characteristic read/write/notify from both GATTS and GATTC.
+
+import sys
+
+sys.path.append("")
+
+from micropython import const
+import time, machine
+
+import uasyncio as asyncio
+import aioble
+import bluetooth
+
+TIMEOUT_MS = 5000
+
+SERVICE_UUID = bluetooth.UUID("A5A5A5A5-FFFF-9999-1111-5A5A5A5A5A5A")
+CHAR1_UUID = bluetooth.UUID("00000000-1111-2222-3333-444444444444")
+CHAR2_UUID = bluetooth.UUID("00000000-1111-2222-3333-555555555555")
+CHAR3_UUID = bluetooth.UUID("00000000-1111-2222-3333-666666666666")
+
+
+# Acting in peripheral role.
+async def instance0_task():
+    service = aioble.Service(SERVICE_UUID)
+    characteristic1 = aioble.BufferedCharacteristic(service, CHAR1_UUID, write=True)
+    characteristic2 = aioble.BufferedCharacteristic(service, CHAR2_UUID, write=True, max_len=40)
+    characteristic3 = aioble.BufferedCharacteristic(
+        service, CHAR3_UUID, write=True, max_len=80, append=True
+    )
+    aioble.register_services(service)
+
+    multitest.globals(BDADDR=aioble.config("mac"))
+    multitest.next()
+
+    # Wait for central to connect to us.
+    print("advertise")
+    connection = await aioble.advertise(
+        20_000, adv_data=b"\x02\x01\x06\x04\xffMPY", timeout_ms=TIMEOUT_MS
+    )
+    print("connected")
+
+    # The first will just see the second write (truncated).
+    await characteristic1.written(timeout_ms=TIMEOUT_MS)
+    await characteristic1.written(timeout_ms=TIMEOUT_MS)
+    print("written", characteristic1.read())
+
+    # The second will just see the second write (still truncated because MTU
+    # exchange hasn't happened).
+    await characteristic2.written(timeout_ms=TIMEOUT_MS)
+    await characteristic2.written(timeout_ms=TIMEOUT_MS)
+    print("written", characteristic2.read())
+
+    # MTU exchange should happen here.
+
+    # The second will now see the full second write.
+    await characteristic2.written(timeout_ms=TIMEOUT_MS)
+    await characteristic2.written(timeout_ms=TIMEOUT_MS)
+    print("written", characteristic2.read())
+
+    # The third will see the two full writes concatenated.
+    await characteristic3.written(timeout_ms=TIMEOUT_MS)
+    await characteristic3.written(timeout_ms=TIMEOUT_MS)
+    print("written", characteristic3.read())
+
+    # Wait for the central to disconnect.
+    await connection.disconnected(timeout_ms=TIMEOUT_MS)
+    print("disconnected")
+
+
+def instance0():
+    try:
+        asyncio.run(instance0_task())
+    finally:
+        aioble.stop()
+
+
+# Acting in central role.
+async def instance1_task():
+    multitest.next()
+
+    # Connect to peripheral and then disconnect.
+    print("connect")
+    device = aioble.Device(*BDADDR)
+    connection = await device.connect(timeout_ms=TIMEOUT_MS)
+
+    # Discover characteristics.
+    service = await connection.service(SERVICE_UUID)
+    print("service", service.uuid)
+    characteristic1 = await service.characteristic(CHAR1_UUID)
+    print("characteristic1", characteristic1.uuid)
+    characteristic2 = await service.characteristic(CHAR2_UUID)
+    print("characteristic2", characteristic2.uuid)
+    characteristic3 = await service.characteristic(CHAR3_UUID)
+    print("characteristic3", characteristic3.uuid)
+
+    # Write to each characteristic twice, with a long enough value to trigger
+    # truncation.
+    print("write1")
+    await characteristic1.write(
+        "central1-aaaaaaaaaaaaaaaaaaaaaaaaaaaaa", response=True, timeout_ms=TIMEOUT_MS
+    )
+    await characteristic1.write(
+        "central1-bbbbbbbbbbbbbbbbbbbbbbbbbbbbb", response=True, timeout_ms=TIMEOUT_MS
+    )
+    print("write2a")
+    await characteristic2.write(
+        "central2a-aaaaaaaaaaaaaaaaaaaaaaaaaaaa", response=True, timeout_ms=TIMEOUT_MS
+    )
+    await characteristic2.write(
+        "central2a-bbbbbbbbbbbbbbbbbbbbbbbbbbbb", response=True, timeout_ms=TIMEOUT_MS
+    )
+    print("exchange mtu")
+    await connection.exchange_mtu(100)
+    print("write2b")
+    await characteristic2.write(
+        "central2b-aaaaaaaaaaaaaaaaaaaaaaaaaaaa", response=True, timeout_ms=TIMEOUT_MS
+    )
+    await characteristic2.write(
+        "central2b-bbbbbbbbbbbbbbbbbbbbbbbbbbbb", response=True, timeout_ms=TIMEOUT_MS
+    )
+    print("write3")
+    await characteristic3.write(
+        "central3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaa", response=True, timeout_ms=TIMEOUT_MS
+    )
+    await characteristic3.write(
+        "central3-bbbbbbbbbbbbbbbbbbbbbbbbbbbbb", response=True, timeout_ms=TIMEOUT_MS
+    )
+
+    # Disconnect from peripheral.
+    print("disconnect")
+    await connection.disconnect(timeout_ms=TIMEOUT_MS)
+    print("disconnected")
+
+
+def instance1():
+    try:
+        asyncio.run(instance1_task())
+    finally:
+        aioble.stop()
diff --git a/micropython/bluetooth/aioble/multitests/ble_buffered_characteristic.py.exp b/micropython/bluetooth/aioble/multitests/ble_buffered_characteristic.py.exp
new file mode 100644
index 0000000..3c00eac
--- /dev/null
+++ b/micropython/bluetooth/aioble/multitests/ble_buffered_characteristic.py.exp
@@ -0,0 +1,21 @@
+--- instance0 ---
+advertise
+connected
+written b'central1-bbbbbbbbbbb'
+written b'central2a-bbbbbbbbbb'
+written b'central2b-bbbbbbbbbbbbbbbbbbbbbbbbbbbb'
+written b'central3-aaaaaaaaaaaaaaaaaaaaaaaaaaaaacentral3-bbbbbbbbbbbbbbbbbbbbbbbbbbbbb'
+disconnected
+--- instance1 ---
+connect
+service UUID('a5a5a5a5-ffff-9999-1111-5a5a5a5a5a5a')
+characteristic1 UUID('00000000-1111-2222-3333-444444444444')
+characteristic2 UUID('00000000-1111-2222-3333-555555555555')
+characteristic3 UUID('00000000-1111-2222-3333-666666666666')
+write1
+write2a
+exchange mtu
+write2b
+write3
+disconnect
+disconnected