diff --git a/.github/workflows/build-cores.yml b/.github/workflows/build-cores.yml
index a9e6153e3..3e0bb1113 100644
--- a/.github/workflows/build-cores.yml
+++ b/.github/workflows/build-cores.yml
@@ -12,6 +12,7 @@ jobs:
         mbed_target:
           - ARDUINO_NANO33BLE
           - RASPBERRY_PI_PICO
+          - ARDUINO_NICLA_SENSE_ME
         cmake_build_type:
           - Debug
           - Release
@@ -23,17 +24,12 @@ jobs:
         uses: actions/checkout@v4
         with:
           submodules: recursive
-  
-      - name: Install Python Dependencies
+
+      - name: Install Python Venv
         run: |
-          # Note: The Mbed container is too old to have python3-json5, but it's old enough that we can
-          # still install python packages globally.
-          # On newer Ubuntu versions, you would instead use:
-          # apt-get update
-          # xargs apt-get install -y < mbed-os/tools/requirements.apt.txt
-          
-          python3 -m pip install -r  mbed-os/tools/requirements.txt
-      
+          apt-get update
+          apt-get install -y python3-venv
+
       - name: Build
         run: |
           mkdir build
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 09f59ea13..111d6c893 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -39,6 +39,7 @@ target_compile_definitions(mbed-os PUBLIC
 # It can't be added as a "regular" Mbed define in mbed-target.config.h because there's
 # some code in ArduinoBLE that looks for this define without including Arduino.h.
 target_compile_definitions(mbed-os PUBLIC ARDUINO_ARCH_MBED=1)
+target_compile_definitions(mbed-core-flags INTERFACE ARDUINO_ARCH_MBED=1)
 
 # Create static library out of mbed-os
 # Note that this library MUST be linked with -Wl,--whole-archive to work.
@@ -70,7 +71,7 @@ set(MBED_LIBS_TO_INSTALL
 	mbed-storage-tdbstore
 )
 
-if("TARGET_USBDEVICE" IN_LIST MBED_TARGET_LABELS)
+if("DEVICE_USBDEVICE=1" IN_LIST MBED_TARGET_DEFINITIONS)
 	list(APPEND MBED_LIBS_TO_INSTALL
 		mbed-usb
 		mbed-usb-cdc-ecm
diff --git a/cores/CMakeLists.txt b/cores/CMakeLists.txt
index 5ee143417..f6fc1f39b 100644
--- a/cores/CMakeLists.txt
+++ b/cores/CMakeLists.txt
@@ -23,7 +23,7 @@ set(ARDUINO_CORE_SOURCES
 add_library(arduino-core STATIC ${ARDUINO_CORE_SOURCES})
 target_link_libraries(arduino-core arduino-api arduino-variant mbed-core-flags mbed-rtos-flags)
 
-if("TARGET_USBDEVICE" IN_LIST MBED_TARGET_LABELS)
+if("DEVICE_USBDEVICE=1" IN_LIST MBED_TARGET_DEFINITIONS)
 	target_link_libraries(arduino-core mbed-usb)
 endif()
 
diff --git a/libraries/CMakeLists.txt b/libraries/CMakeLists.txt
index b19646c75..9283dc13f 100644
--- a/libraries/CMakeLists.txt
+++ b/libraries/CMakeLists.txt
@@ -48,7 +48,7 @@ add_subdirectory(Wire)
 add_subdirectory(SPI)
 add_subdirectory(Scheduler)
 
-if("TARGET_USBDEVICE" IN_LIST MBED_TARGET_LABELS)
+if("DEVICE_USBDEVICE=1" IN_LIST MBED_TARGET_DEFINITIONS)
 	add_subdirectory(USBHID)
 	add_subdirectory(USBMIDI)
 	add_subdirectory(USBMSD)
diff --git a/libraries/Wire/Wire.cpp b/libraries/Wire/Wire.cpp
index e77b00936..e744a8c47 100644
--- a/libraries/Wire/Wire.cpp
+++ b/libraries/Wire/Wire.cpp
@@ -23,9 +23,9 @@
 #include "Wire.h"
 #include "pinDefinitions.h"
 
-arduino::MbedI2C::MbedI2C(int sda, int scl) : _sda(digitalPinToPinName(sda)), _scl(digitalPinToPinName(scl)), usedTxBuffer(0) {}
+arduino::MbedI2C::MbedI2C(int sda, int scl) : _sda(digitalPinToPinName(sda)), _scl(digitalPinToPinName(scl)), usedTxBuffer(0), txBufferOverflow(false) {}
 
-arduino::MbedI2C::MbedI2C(PinName sda, PinName scl) : _sda(sda), _scl(scl), usedTxBuffer(0) {}
+arduino::MbedI2C::MbedI2C(PinName sda, PinName scl) : _sda(sda), _scl(scl), usedTxBuffer(0), txBufferOverflow(false) {}
 
 void arduino::MbedI2C::begin() {
 	end();
@@ -72,19 +72,30 @@ void arduino::MbedI2C::setClock(uint32_t freq) {
 void arduino::MbedI2C::beginTransmission(uint8_t address) {
 	_address = address << 1;
 	usedTxBuffer = 0;
+    txBufferOverflow = false;
 }
 
 uint8_t arduino::MbedI2C::endTransmission(bool stopBit) {
-	#ifndef TARGET_PORTENTA_H7
-	if (usedTxBuffer == 0) {
-		// we are scanning, return 0 if the addresed device responds with an ACK
-		char buf[1];
-		int ret = master->read(_address, buf, 1, !stopBit);
-		return ret;
-	}
-	#endif
-	if (master->write(_address, (const char *) txBuffer, usedTxBuffer, !stopBit) == mbed::I2C::Result::ACK) return 0;
-	return 2;
+
+    mbed::I2C::Result writeResult = master->write(_address, (const char *) txBuffer, usedTxBuffer, !stopBit);
+    if (writeResult == mbed::I2C::Result::NACK) {
+        return 2; // Indicate NACK.  No way to tell if received during address or data, but assume address.
+    }
+    else if (writeResult == mbed::I2C::Result::ACK) {
+        if (txBufferOverflow) {
+            return 1;
+        }
+        else {
+           // Success
+           return 0;
+        }
+    }
+    else if (writeResult == mbed::I2C::Result::TIMEOUT) {
+        return 5; // timeout
+    }
+    else {
+        return 4; // other error
+    }
 }
 
 uint8_t arduino::MbedI2C::endTransmission(void) {
@@ -92,12 +103,9 @@ uint8_t arduino::MbedI2C::endTransmission(void) {
 }
 
 size_t arduino::MbedI2C::requestFrom(uint8_t address, size_t len, bool stopBit) {
-	if(len > BufferSize)
-    {
-        return 0;
-    }
 
     char buf[BufferSize];
+    len = min(len, sizeof(buf));
 
 	auto ret = master->read(address << 1, buf, len, !stopBit);
 	if (ret != mbed::I2C::Result::ACK) {
@@ -114,13 +122,19 @@ size_t arduino::MbedI2C::requestFrom(uint8_t address, size_t len) {
 }
 
 size_t arduino::MbedI2C::write(uint8_t data) {
-	if (usedTxBuffer == BufferSize) return 0;
+	if (usedTxBuffer == BufferSize) {
+        txBufferOverflow = true;
+        return 0;
+    }
 	txBuffer[usedTxBuffer++] = data;
 	return 1;
 }
 
 size_t arduino::MbedI2C::write(const uint8_t* data, int len) {
-	if (usedTxBuffer + len > BufferSize) len = BufferSize - usedTxBuffer;
+	if (usedTxBuffer + len > BufferSize) {
+        txBufferOverflow = true;
+        len = BufferSize - usedTxBuffer;
+    }
 	memcpy(txBuffer + usedTxBuffer, data, len);
 	usedTxBuffer += len;
 	return len;
diff --git a/libraries/Wire/Wire.h b/libraries/Wire/Wire.h
index 8a8b38622..960c99702 100644
--- a/libraries/Wire/Wire.h
+++ b/libraries/Wire/Wire.h
@@ -80,6 +80,7 @@ class MbedI2C : public HardwareI2C
     RingBufferN<BufferSize> rxBuffer;
     uint8_t txBuffer[BufferSize];
     uint32_t usedTxBuffer;
+    bool txBufferOverflow;
     voidFuncPtrParamInt onReceiveCb = NULL;
     voidFuncPtr onRequestCb = NULL;
 #ifdef DEVICE_I2CSLAVE
diff --git a/mbed-os b/mbed-os
index dbbc25923..87bc6de65 160000
--- a/mbed-os
+++ b/mbed-os
@@ -1 +1 @@
-Subproject commit dbbc25923bb92b709d971788072e2a9175fedc36
+Subproject commit 87bc6de65a3943d2f1cdba22da70af6b592e2ec7