diff --git a/src/lib/spinel/logger.cpp b/src/lib/spinel/logger.cpp
index d1cb86178..97fb18c68 100644
--- a/src/lib/spinel/logger.cpp
+++ b/src/lib/spinel/logger.cpp
@@ -446,6 +446,7 @@ void Logger::LogSpinelFrame(const uint8_t *aFrame, uint16_t aLength, bool aTx)
             uint16_t     flags;
             int8_t       noiseFloor;
             unsigned int receiveError;
+            unsigned int psduLength;
 
             unpacked = spinel_datatype_unpack(data, len,
                                               SPINEL_DATATYPE_DATA_WLEN_S                          // Frame
@@ -459,10 +460,12 @@ void Logger::LogSpinelFrame(const uint8_t *aFrame, uint16_t aLength, bool aTx)
                                                                   ) SPINEL_DATATYPE_STRUCT_S(      // Vendor-data
                                                                   SPINEL_DATATYPE_UINT_PACKED_S    // Receive error
                                                                   ),
-                                              &frame.mPsdu, &frame.mLength, &frame.mInfo.mRxInfo.mRssi, &noiseFloor,
-                                              &flags, &frame.mChannel, &frame.mInfo.mRxInfo.mLqi,
+                                              nullptr, &psduLength, &frame.mInfo.mRxInfo.mRssi, &noiseFloor, &flags,
+                                              &frame.mChannel, &frame.mInfo.mRxInfo.mLqi,
                                               &frame.mInfo.mRxInfo.mTimestamp, &receiveError);
             VerifyOrExit(unpacked > 0, error = OT_ERROR_PARSE);
+            frame.mLength = static_cast<uint16_t>(psduLength);
+
             start += Snprintf(start, static_cast<uint32_t>(end - start), ", len:%u, rssi:%d ...", frame.mLength,
                               frame.mInfo.mRxInfo.mRssi);
             OT_UNUSED_VARIABLE(start); // Avoid static analysis error
@@ -476,10 +479,11 @@ void Logger::LogSpinelFrame(const uint8_t *aFrame, uint16_t aLength, bool aTx)
         }
         else if (cmd == SPINEL_CMD_PROP_VALUE_SET)
         {
-            bool csmaCaEnabled;
-            bool isHeaderUpdated;
-            bool isARetx;
-            bool skipAes;
+            unsigned int psduLength;
+            bool         csmaCaEnabled;
+            bool         isHeaderUpdated;
+            bool         isARetx;
+            bool         skipAes;
 
             unpacked = spinel_datatype_unpack(
                 data, len,
@@ -493,11 +497,13 @@ void Logger::LogSpinelFrame(const uint8_t *aFrame, uint16_t aLength, bool aTx)
                                             SPINEL_DATATYPE_BOOL_S            // SkipAes
                                                 SPINEL_DATATYPE_UINT32_S      // TxDelay
                                                     SPINEL_DATATYPE_UINT32_S, // TxDelayBaseTime
-                &frame.mPsdu, &frame.mLength, &frame.mChannel, &frame.mInfo.mTxInfo.mMaxCsmaBackoffs,
+                nullptr, &psduLength, &frame.mChannel, &frame.mInfo.mTxInfo.mMaxCsmaBackoffs,
                 &frame.mInfo.mTxInfo.mMaxFrameRetries, &csmaCaEnabled, &isHeaderUpdated, &isARetx, &skipAes,
                 &frame.mInfo.mTxInfo.mTxDelay, &frame.mInfo.mTxInfo.mTxDelayBaseTime);
 
             VerifyOrExit(unpacked > 0, error = OT_ERROR_PARSE);
+            frame.mLength = static_cast<uint16_t>(psduLength);
+
             start += Snprintf(start, static_cast<uint32_t>(end - start),
                               ", len:%u, channel:%u, maxbackoffs:%u, maxretries:%u ...", frame.mLength, frame.mChannel,
                               frame.mInfo.mTxInfo.mMaxCsmaBackoffs, frame.mInfo.mTxInfo.mMaxFrameRetries);
@@ -547,9 +553,8 @@ void Logger::LogSpinelFrame(const uint8_t *aFrame, uint16_t aLength, bool aTx)
     case SPINEL_PROP_NEST_STREAM_MFG:
     {
         const char *output;
-        size_t      outputLen;
 
-        unpacked = spinel_datatype_unpack(data, len, SPINEL_DATATYPE_UTF8_S, &output, &outputLen);
+        unpacked = spinel_datatype_unpack(data, len, SPINEL_DATATYPE_UTF8_S, &output);
         VerifyOrExit(unpacked > 0, error = OT_ERROR_PARSE);
         start += Snprintf(start, static_cast<uint32_t>(end - start), ", diag:%s", output);
     }
@@ -566,11 +571,11 @@ void Logger::LogSpinelFrame(const uint8_t *aFrame, uint16_t aLength, bool aTx)
         otMacKey     nextKey;
         unsigned int nextKeyLen = sizeof(otMacKey);
 
-        unpacked = spinel_datatype_unpack(data, len,
-                                          SPINEL_DATATYPE_UINT8_S SPINEL_DATATYPE_UINT8_S SPINEL_DATATYPE_DATA_WLEN_S
-                                              SPINEL_DATATYPE_DATA_WLEN_S SPINEL_DATATYPE_DATA_WLEN_S,
-                                          &keyIdMode, &keyId, prevKey.m8, &prevKeyLen, currKey.m8, &currKeyLen,
-                                          nextKey.m8, &nextKeyLen);
+        unpacked = spinel_datatype_unpack_in_place(
+            data, len,
+            SPINEL_DATATYPE_UINT8_S SPINEL_DATATYPE_UINT8_S SPINEL_DATATYPE_DATA_WLEN_S SPINEL_DATATYPE_DATA_WLEN_S
+                SPINEL_DATATYPE_DATA_WLEN_S,
+            &keyIdMode, &keyId, prevKey.m8, &prevKeyLen, currKey.m8, &currKeyLen, nextKey.m8, &nextKeyLen);
         VerifyOrExit(unpacked > 0, error = OT_ERROR_PARSE);
         start += Snprintf(start, static_cast<uint32_t>(end - start),
                           ", keyIdMode:%u, keyId:%u, prevKey:***, currKey:***, nextKey:***", keyIdMode, keyId);
@@ -681,11 +686,10 @@ void Logger::LogSpinelFrame(const uint8_t *aFrame, uint16_t aLength, bool aTx)
 
     case SPINEL_PROP_MAC_SCAN_MASK:
     {
-        constexpr uint8_t kNumChannels = 16;
-        uint8_t           channels[kNumChannels];
-        spinel_size_t     size;
+        const uint8_t *channels;
+        spinel_size_t  size;
 
-        unpacked = spinel_datatype_unpack(data, len, SPINEL_DATATYPE_DATA_S, channels, &size);
+        unpacked = spinel_datatype_unpack(data, len, SPINEL_DATATYPE_DATA_S, &channels, &size);
         VerifyOrExit(unpacked > 0, error = OT_ERROR_PARSE);
         start += Snprintf(start, static_cast<uint32_t>(end - start), ", channels:");
 
@@ -702,7 +706,7 @@ void Logger::LogSpinelFrame(const uint8_t *aFrame, uint16_t aLength, bool aTx)
         uint8_t  m8[OT_EXT_ADDRESS_SIZE];
         uint8_t  flags;
 
-        unpacked = spinel_datatype_unpack(
+        unpacked = spinel_datatype_unpack_in_place(
             data, len, SPINEL_DATATYPE_UINT16_S SPINEL_DATATYPE_EUI64_S SPINEL_DATATYPE_UINT8_S, &saddr, m8, &flags);
 
         VerifyOrExit(unpacked > 0, error = OT_ERROR_PARSE);
@@ -716,10 +720,10 @@ void Logger::LogSpinelFrame(const uint8_t *aFrame, uint16_t aLength, bool aTx)
     {
         if (cmd == SPINEL_CMD_PROP_VALUE_INSERT)
         {
-            uint8_t      channel;
-            int16_t      actualPower;
-            uint8_t     *rawPowerSetting;
-            unsigned int rawPowerSettingLength;
+            uint8_t        channel;
+            int16_t        actualPower;
+            const uint8_t *rawPowerSetting;
+            unsigned int   rawPowerSettingLength;
 
             unpacked = spinel_datatype_unpack(
                 data, len, SPINEL_DATATYPE_UINT8_S SPINEL_DATATYPE_INT16_S SPINEL_DATATYPE_DATA_WLEN_S, &channel,