diff --git a/examples/platforms/cc2650/openthread-core-cc2650-config.h b/examples/platforms/cc2650/openthread-core-cc2650-config.h
index c03f7b957..ebeeeee48 100644
--- a/examples/platforms/cc2650/openthread-core-cc2650-config.h
+++ b/examples/platforms/cc2650/openthread-core-cc2650-config.h
@@ -36,13 +36,5 @@
  */
 #define OPENTHREAD_CONFIG_NUM_MESSAGE_BUFFERS 32
 
-/**
-  * @def OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
-  *
-  * Define to 1 if you want use legacy transmit done.
-  *
-  */
-#define OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE 1
-
 #endif /* OPENTHREAD_CORE_CC2650_CONFIG_H_ */
 
diff --git a/examples/platforms/cc2650/radio.c b/examples/platforms/cc2650/radio.c
index 5b15dca5d..fd4a2589d 100644
--- a/examples/platforms/cc2650/radio.c
+++ b/examples/platforms/cc2650/radio.c
@@ -51,6 +51,7 @@
 
 enum
 {
+    IEEE802154_ACK_LENGTH = 5,
     CC2650_RECEIVE_SENSITIVITY = -100,  // dBm
 };
 
@@ -1840,7 +1841,23 @@ void cc2650RadioProcess(otInstance *aInstance)
         else
 #endif /* OPENTHREAD_ENABLE_DIAG */
         {
-            otPlatRadioTransmitDone(aInstance, &sTransmitFrame, sReceivedAckPendingBit, sTransmitError);
+            // TODO: pass received ACK frame instead of generating one.
+            otRadioFrame ackFrame;
+            uint8_t psdu[IEEE802154_ACK_LENGTH];
+
+            ackFrame.mPsdu = psdu;
+            ackFrame.mLength = IEEE802154_ACK_LENGTH;
+            ackFrame.mPsdu[0] = IEEE802154_FRAME_TYPE_ACK;
+
+            if (sReceivedAckPendingBit)
+            {
+                ackFrame.mPsdu[0] |= IEEE802154_FRAME_PENDING;
+            }
+
+            ackFrame.mPsdu[1] = 0;
+            ackFrame.mPsdu[2] = sTransmitFrame.mPsdu[IEEE802154_DSN_OFFSET];
+
+            otPlatRadioTxDone(aInstance, &sTransmitFrame, &ackFrame, sTransmitError);
         }
     }
 
diff --git a/examples/platforms/cc2652/openthread-core-cc2652-config.h b/examples/platforms/cc2652/openthread-core-cc2652-config.h
index 71dde962e..baffdad0b 100644
--- a/examples/platforms/cc2652/openthread-core-cc2652-config.h
+++ b/examples/platforms/cc2652/openthread-core-cc2652-config.h
@@ -60,13 +60,5 @@
  */
 #define OPENTHREAD_CONFIG_ENABLE_DEFAULT_LOG_OUTPUT        1
 
-/**
-  * @def OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
-  *
-  * Define to 1 if you want use legacy transmit done.
-  *
-  */
-#define OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE             1
-
 #endif /* OPENTHREAD_CORE_CC2650_CONFIG_H_ */
 
diff --git a/examples/platforms/cc2652/radio.c b/examples/platforms/cc2652/radio.c
index b5721a2f0..c6c7aa0a1 100644
--- a/examples/platforms/cc2652/radio.c
+++ b/examples/platforms/cc2652/radio.c
@@ -61,6 +61,7 @@
 
 enum
 {
+    IEEE802154_ACK_LENGTH = 5,
     CC2652_RECEIVE_SENSITIVITY = -100,  // dBm
 };
 
@@ -1838,7 +1839,23 @@ void cc2652RadioProcess(otInstance *aInstance)
         else
 #endif /* OPENTHREAD_ENABLE_DIAG */
         {
-            otPlatRadioTransmitDone(aInstance, &sTransmitFrame, sReceivedAckPendingBit, sTransmitError);
+            // TODO: pass received ACK frame instead of generating one.
+            otRadioFrame ackFrame;
+            uint8_t psdu[IEEE802154_ACK_LENGTH];
+
+            ackFrame.mPsdu = psdu;
+            ackFrame.mLength = IEEE802154_ACK_LENGTH;
+            ackFrame.mPsdu[0] = IEEE802154_FRAME_TYPE_ACK;
+
+            if (sReceivedAckPendingBit)
+            {
+                ackFrame.mPsdu[0] |= IEEE802154_FRAME_PENDING;
+            }
+
+            ackFrame.mPsdu[1] = 0;
+            ackFrame.mPsdu[2] = sTransmitFrame.mPsdu[IEEE802154_DSN_OFFSET];
+
+            otPlatRadioTxDone(aInstance, &sTransmitFrame, &ackFrame, sTransmitError);
         }
     }
 
diff --git a/examples/platforms/gp712/Makefile.am b/examples/platforms/gp712/Makefile.am
index 9d7ced4f3..666fa55f9 100644
--- a/examples/platforms/gp712/Makefile.am
+++ b/examples/platforms/gp712/Makefile.am
@@ -30,19 +30,17 @@ include $(abs_top_nlbuild_autotools_dir)/automake/pre.am
 
 lib_LIBRARIES                             = libopenthread-gp712.a
 
-libopenthread_gp712_a_CPPFLAGS           =  \
+libopenthread_gp712_a_CPPFLAGS            = \
     -I$(top_srcdir)/include                 \
     -I$(top_srcdir)/examples/platforms      \
-    -I$(top_srcdir)/examples/platforms/utils\
     -I$(top_srcdir)/src/core                \
     -lrt                                    \
     -lpthread                               \
     $(NULL)
 
-libopenthread_gp712_settings.cpp: $(srcdir)/../utils/settings.cpp
-	cp $? $@
-
-CLEANFILES = libopenthread_gp712_settings.cpp
+Dash                                      = -
+libopenthread_gp712_a_LIBADD              = \
+    $(shell find $(top_builddir)/examples/platforms/utils $(Dash)type f $(Dash)name "*.o")
 
 libopenthread_gp712_a_SOURCES             = \
     alarm.c                                 \
@@ -53,7 +51,6 @@ libopenthread_gp712_a_SOURCES             = \
     random.c                                \
     uart-posix.c                            \
     flash.c                                 \
-    libopenthread_gp712_settings.cpp        \
     $(NULL)
 
 #    uart-socket.c                           \
@@ -67,7 +64,7 @@ endif
 
 
 if OPENTHREAD_BUILD_COVERAGE
-CLEANFILES                               += $(wildcard *.gcda *.gcno)
+CLEANFILES                                = $(wildcard *.gcda *.gcno)
 endif # OPENTHREAD_BUILD_COVERAGE
 
 include $(abs_top_nlbuild_autotools_dir)/automake/post.am
diff --git a/examples/platforms/gp712/alarm.c b/examples/platforms/gp712/alarm.c
index 900352a3f..d117e048c 100644
--- a/examples/platforms/gp712/alarm.c
+++ b/examples/platforms/gp712/alarm.c
@@ -38,7 +38,7 @@
 
 #include <openthread/openthread.h>
 #include <openthread/platform/platform.h>
-#include <openthread/platform/alarm.h>
+#include <openthread/platform/alarm-milli.h>
 #include <openthread/platform/diag.h>
 #include "alarm_qorvo.h"
 
@@ -46,24 +46,24 @@ void qorvoAlarmInit(void)
 {
 }
 
-uint32_t otPlatAlarmGetNow(void)
+uint32_t otPlatAlarmMilliGetNow(void)
 {
     return qorvoAlarmGetTimeMs();
 }
 
 static void qorvoAlarmFired(void *aInstance)
 {
-    otPlatAlarmFired((otInstance *)aInstance);
+    otPlatAlarmMilliFired((otInstance *)aInstance);
 }
 
-void otPlatAlarmStartAt(otInstance *aInstance, uint32_t t0, uint32_t dt)
+void otPlatAlarmMilliStartAt(otInstance *aInstance, uint32_t t0, uint32_t dt)
 {
     (void)t0;
     qorvoAlarmUnScheduleEventArg((qorvoAlarmCallback_t)qorvoAlarmFired, aInstance);
     qorvoAlarmScheduleEventArg(dt * 1000, qorvoAlarmFired, aInstance);
 }
 
-void otPlatAlarmStop(otInstance *aInstance)
+void otPlatAlarmMilliStop(otInstance *aInstance)
 {
     qorvoAlarmUnScheduleEventArg((qorvoAlarmCallback_t)qorvoAlarmFired, aInstance);
 }
diff --git a/examples/platforms/gp712/diag.c b/examples/platforms/gp712/diag.c
index 268ff6e45..a70c5b200 100644
--- a/examples/platforms/gp712/diag.c
+++ b/examples/platforms/gp712/diag.c
@@ -33,7 +33,7 @@
 
 #include <openthread/config.h>
 #include <openthread/openthread.h>
-#include <openthread/platform/alarm.h>
+#include <openthread/platform/alarm-milli.h>
 #include <openthread/platform/radio.h>
 
 /**
diff --git a/examples/platforms/gp712/openthread-core-gp712-config.h b/examples/platforms/gp712/openthread-core-gp712-config.h
index d9c7ba8a0..933b3652f 100644
--- a/examples/platforms/gp712/openthread-core-gp712-config.h
+++ b/examples/platforms/gp712/openthread-core-gp712-config.h
@@ -34,13 +34,4 @@
 #ifndef OPENTHREAD_CORE_GP712_CONFIG_H_
 #define OPENTHREAD_CORE_GP712_CONFIG_H_
 
-/**
-  * @def OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
-  *
-  * Define to 1 if you want use legacy transmit done.
-  *
-  */
-#define OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE 1
-
-
 #endif  // OPENTHREAD_CORE_GP712_CONFIG_H_
diff --git a/examples/platforms/gp712/radio.c b/examples/platforms/gp712/radio.c
index dc473b808..c5327914b 100644
--- a/examples/platforms/gp712/radio.c
+++ b/examples/platforms/gp712/radio.c
@@ -196,7 +196,23 @@ exit:
 
 void cbQorvoRadioTransmitDone(otRadioFrame *aPacket, bool aFramePending, otError aError)
 {
-    otPlatRadioTransmitDone(pQorvoInstance, aPacket, aFramePending, aError);
+    // TODO: pass received ACK frame instead of generating one.
+    otRadioFrame ackFrame;
+    uint8_t psdu[IEEE802154_ACK_LENGTH];
+
+    ackFrame.mPsdu = psdu;
+    ackFrame.mLength = IEEE802154_ACK_LENGTH;
+    ackFrame.mPsdu[0] = IEEE802154_FRAME_TYPE_ACK;
+
+    if (aFramePending)
+    {
+        ackFrame.mPsdu[0] |= IEEE802154_FRAME_PENDING;
+    }
+
+    ackFrame.mPsdu[1] = 0;
+    ackFrame.mPsdu[2] = aPacket->mPsdu[IEEE802154_DSN_OFFSET];
+
+    otPlatRadioTxDone(pQorvoInstance, aPacket, &ackFrame, aError);
 }
 
 void cbQorvoRadioReceiveDone(otRadioFrame *aPacket, otError aError)
diff --git a/examples/platforms/posix/radio.c b/examples/platforms/posix/radio.c
index 56f786d44..c9a4becab 100644
--- a/examples/platforms/posix/radio.c
+++ b/examples/platforms/posix/radio.c
@@ -588,21 +588,21 @@ void platformRadioProcess(otInstance *aInstance)
     }
 }
 
-void radioTransmit(struct RadioMessage *msg, const struct otRadioFrame *pkt)
+void radioTransmit(struct RadioMessage *aMessage, const struct otRadioFrame *aFrame)
 {
     uint32_t i;
     struct sockaddr_in sockaddr;
 
     uint16_t crc = 0;
-    uint16_t crc_offset = pkt->mLength - sizeof(uint16_t);
+    uint16_t crc_offset = aFrame->mLength - sizeof(uint16_t);
 
     for (i = 0; i < crc_offset; i++)
     {
-        crc = crc16_citt(crc, msg->mPsdu[i]);
+        crc = crc16_citt(crc, aMessage->mPsdu[i]);
     }
 
-    msg->mPsdu[crc_offset] = crc & 0xff;
-    msg->mPsdu[crc_offset + 1] = crc >> 8;
+    aMessage->mPsdu[crc_offset] = crc & 0xff;
+    aMessage->mPsdu[crc_offset + 1] = crc >> 8;
 
     memset(&sockaddr, 0, sizeof(sockaddr));
     sockaddr.sin_family = AF_INET;
@@ -618,7 +618,7 @@ void radioTransmit(struct RadioMessage *msg, const struct otRadioFrame *pkt)
         }
 
         sockaddr.sin_port = htons(9000 + sPortOffset + i);
-        rval = sendto(sSockFd, (const char *)msg, 1 + pkt->mLength,
+        rval = sendto(sSockFd, (const char *)aMessage, 1 + aFrame->mLength,
                       0, (struct sockaddr *)&sockaddr, sizeof(sockaddr));
 
         if (rval < 0)
diff --git a/include/openthread/platform/radio.h b/include/openthread/platform/radio.h
index 3430b829b..7032cd1d9 100644
--- a/include/openthread/platform/radio.h
+++ b/include/openthread/platform/radio.h
@@ -420,22 +420,6 @@ extern void otPlatRadioTxStarted(otInstance *aInstance, otRadioFrame *aFrame);
 extern void otPlatRadioTxDone(otInstance *aInstance, otRadioFrame *aFrame, otRadioFrame *aAckFrame,
                               otError aError);
 
-/**
- * The radio driver calls this method to notify OpenThread that the transmission has completed,
- * this function is going to be deprecated, new add platfroms should not use this callback function.
- *
- * @param[in]  aInstance      The OpenThread instance structure.
- * @param[in]  aFrame         A pointer to the frame that was transmitted.
- * @param[in]  aFramePending  TRUE if an ACK frame was received and the Frame Pending bit was set.
- * @param[in]  aError         OT_ERROR_NONE when the frame was transmitted, OT_ERROR_NO_ACK when the frame was
- *                            transmitted but no ACK was received, OT_ERROR_CHANNEL_ACCESS_FAILURE when the transmission
- *                            could not take place due to activity on the channel, OT_ERROR_ABORT when transmission was
- *                            aborted for other reasons.
- *
- */
-extern void otPlatRadioTransmitDone(otInstance *aInstance, otRadioFrame *aFrame, bool aFramePending,
-                                    otError aError);
-
 /**
  * Get the most recent RSSI measurement.
  *
diff --git a/src/core/mac/mac.cpp b/src/core/mac/mac.cpp
index 4d58acef8..0ee80de77 100644
--- a/src/core/mac/mac.cpp
+++ b/src/core/mac/mac.cpp
@@ -849,11 +849,7 @@ exit:
 
     if (error != OT_ERROR_NONE)
     {
-#if OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
-        TransmitDoneTask(mTxFrame, false, OT_ERROR_ABORT);
-#else
         TransmitDoneTask(mTxFrame, NULL, OT_ERROR_ABORT);
-#endif
     }
 }
 
@@ -877,103 +873,6 @@ void Mac::TransmitStartedTask(otRadioFrame *aFrame)
     }
 }
 
-#if OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
-extern "C" void otPlatRadioTransmitDone(otInstance *aInstance, otRadioFrame *aFrame, bool aRxPending,
-                                        otError aError)
-{
-    otLogFuncEntryMsg("%!otError!, aRxPending=%u", aError, aRxPending ? 1 : 0);
-    VerifyOrExit(otInstanceIsInitialized(aInstance));
-
-#if OPENTHREAD_ENABLE_RAW_LINK_API
-
-    if (aInstance->mLinkRaw.IsEnabled())
-    {
-        aInstance->mLinkRaw.InvokeTransmitDone(aFrame, aRxPending, aError);
-    }
-    else
-#endif // OPENTHREAD_ENABLE_RAW_LINK_API
-    {
-        aInstance->mThreadNetif.GetMac().TransmitDoneTask(aFrame, aRxPending, aError);
-    }
-
-exit:
-    otLogFuncExit();
-}
-
-void Mac::TransmitDoneTask(otRadioFrame *aFrame, bool aRxPending, otError aError)
-{
-    mMacTimer.Stop();
-
-    mCounters.mTxTotal++;
-
-    Frame *frame = static_cast<Frame *>(aFrame);
-    Address addr;
-    frame->GetDstAddr(addr);
-
-    if (addr.mShortAddress == kShortAddrBroadcast)
-    {
-        // Broadcast frame
-        mCounters.mTxBroadcast++;
-    }
-    else
-    {
-        // Unicast frame
-        mCounters.mTxUnicast++;
-    }
-
-    if (aError == OT_ERROR_ABORT)
-    {
-        mCounters.mTxErrAbort++;
-    }
-
-    if (aError == OT_ERROR_CHANNEL_ACCESS_FAILURE)
-    {
-        mCounters.mTxErrCca++;
-    }
-
-    if (!RadioSupportsCsmaBackoff() &&
-        aError == OT_ERROR_CHANNEL_ACCESS_FAILURE &&
-        mCsmaAttempts < kMaxCSMABackoffs)
-    {
-        mCsmaAttempts++;
-        StartCsmaBackoff();
-
-        ExitNow();
-    }
-
-    mCsmaAttempts = 0;
-
-    switch (mState)
-    {
-    case kStateTransmitData:
-    {
-        uint8_t commandId;
-
-        if ((frame->GetType() == Frame::kFcfFrameMacCmd) && (frame->GetCommandId(commandId) == OT_ERROR_NONE) &&
-            (commandId == Frame::kMacCmdDataRequest) && (aRxPending))
-        {
-            mWaitingForData = true;
-            mReceiveTimer.Start(kDataPollTimeout);
-        }
-    }
-
-    // fall through
-
-    case kStateActiveScan:
-    case kStateTransmitBeacon:
-        SentFrame(aError);
-        break;
-
-    default:
-        assert(false);
-        break;
-    }
-
-exit:
-    return;
-}
-
-#else // #if OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
 extern "C" void otPlatRadioTxDone(otInstance *aInstance, otRadioFrame *aFrame, otRadioFrame *aAckFrame,
                                   otError aError)
 {
@@ -1085,8 +984,6 @@ exit:
     return;
 }
 
-#endif // OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
-
 otError Mac::RadioTransmit(Frame *aSendFrame)
 {
 #if OPENTHREAD_CONFIG_STAY_AWAKE_BETWEEN_FRAGMENTS
diff --git a/src/core/mac/mac.hpp b/src/core/mac/mac.hpp
index 165dd684e..b08d07018 100644
--- a/src/core/mac/mac.hpp
+++ b/src/core/mac/mac.hpp
@@ -508,21 +508,6 @@ public:
      */
     void TransmitStartedTask(otRadioFrame *aFrame);
 
-#if OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
-    /**
-     * This method is called to handle transmit events.
-     *
-     * @param[in]  aFrame         A pointer to the frame that was transmitted.
-     * @param[in]  aFramePending  TRUE if an ACK frame was received and the Frame Pending bit was set.
-     * @param[in]  aError         OT_ERROR_NONE when the frame was transmitted, OT_ERROR_NO_ACK when the frame was
-     *                            transmitted but no ACK was received, OT_ERROR_CHANNEL_ACCESS_FAILURE when the
-     *                            transmission could not take place due to activity on the channel, OT_ERROR_ABORT when
-     *                            transmission was aborted for other reasons.
-     *
-     */
-    void TransmitDoneTask(otRadioFrame *aFrame, bool aRxPending, otError aError);
-
-#else // #if OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
     /**
      * This method is called to handle transmit events.
      *
@@ -535,7 +520,6 @@ public:
      *
      */
     void TransmitDoneTask(otRadioFrame *aFrame, otRadioFrame *aAckFrame, otError aError);
-#endif // OPENTHREAD_CONFIG_LEGACY_TRANSMIT_DONE
 
     /**
      * This method returns if an active scan is in progress.