diff --git a/rigs/guohetec/guohetec.c b/rigs/guohetec/guohetec.c
index d5019c39a..d2d797c1c 100644
--- a/rigs/guohetec/guohetec.c
+++ b/rigs/guohetec/guohetec.c
@@ -189,7 +189,7 @@ int read_rig_response(RIG *rig, unsigned char *reply, int reply_size,
  * @param func_name Function name for debug messages
  * @return 0 on success, -1 on error
  */
-int validate_rig_response(RIG *rig, unsigned char *reply, int reply_size, 
+int validate_rig_response(RIG *rig, const unsigned char *reply, int reply_size, 
                          const char *func_name)
 {
     // Validate packet header
@@ -213,7 +213,7 @@ int validate_rig_response(RIG *rig, unsigned char *reply, int reply_size,
  * @param func_name Function name for debug messages
  * @return 0 on success, -1 on error
  */
-int validate_freq_response(RIG *rig, unsigned char *reply, int reply_size, 
+int validate_freq_response(RIG *rig, const unsigned char *reply, int reply_size, 
                           const char *func_name)
 {
     // Basic validation
@@ -257,7 +257,7 @@ int validate_freq_response(RIG *rig, unsigned char *reply, int reply_size,
  * @param min_length Minimum required data length
  * @return 0 on success, -1 on error
  */
-int validate_mode_response(RIG *rig, unsigned char *reply, int reply_size, 
+int validate_mode_response(RIG *rig, const unsigned char *reply, int reply_size, 
                           const char *func_name, int min_length)
 {
     // Basic validation
@@ -305,8 +305,6 @@ DECLARE_PROBERIG_BACKEND(guohetec) {
         0x0B,                   
         0x00, 0x00              
     };
-    
-    uint8_t reply[PMR171_REPLY_LENGTH];
 
     int orig_rate = port->parm.serial.rate;
     int orig_timeout = port->timeout;
@@ -314,6 +312,8 @@ DECLARE_PROBERIG_BACKEND(guohetec) {
     const int rates[] = {9600, 19200, 38400, 57600, 115200, 0};
     
     for (int i = 0; rates[i]; i++) {
+        uint8_t reply[PMR171_REPLY_LENGTH];
+        
         port->parm.serial.rate = rates[i];
         port->timeout = 500; 
         
diff --git a/rigs/guohetec/guohetec.h b/rigs/guohetec/guohetec.h
index 589e2e3f7..06d944f54 100644
--- a/rigs/guohetec/guohetec.h
+++ b/rigs/guohetec/guohetec.h
@@ -61,13 +61,13 @@ unsigned char *to_be(unsigned char data[], unsigned long long freq, unsigned int
 unsigned long long from_be(const unsigned char data[],unsigned int byte_len);
 
 // Common response validation functions
-int validate_rig_response(RIG *rig, unsigned char *reply, int reply_size, 
+int validate_rig_response(RIG *rig, const unsigned char *reply, int reply_size, 
                          const char *func_name);
 int read_rig_response(RIG *rig, unsigned char *reply, int reply_size, 
                      const char *func_name);
-int validate_freq_response(RIG *rig, unsigned char *reply, int reply_size, 
+int validate_freq_response(RIG *rig, const unsigned char *reply, int reply_size, 
                           const char *func_name);
-int validate_mode_response(RIG *rig, unsigned char *reply, int reply_size, 
+int validate_mode_response(RIG *rig, const unsigned char *reply, int reply_size, 
                           const char *func_name, int min_length);
 
 #endif // _guohetec_H_
diff --git a/rigs/guohetec/pmr171.c b/rigs/guohetec/pmr171.c
index 51183af98..38a5ada07 100644
--- a/rigs/guohetec/pmr171.c
+++ b/rigs/guohetec/pmr171.c
@@ -367,39 +367,39 @@ static int pmr171_open(RIG *rig)
     cmd[6] = crc >> 8;
     cmd[7] = crc & 0xFF;
 
-    // Receive buffer and send command
-    unsigned char reply[40];
-    pmr171_send(rig, cmd, sizeof(cmd), reply, sizeof(reply));
+    {
+        unsigned char reply[40];
+        pmr171_send(rig, cmd, sizeof(cmd), reply, sizeof(reply));
 
-    // Validate response using common function
-    if (validate_freq_response(rig, reply, sizeof(reply), __func__) < 0) {
-        RETURN_CACHED_FREQ(rig, vfo, freq);
+        // Validate response using common function
+        if (validate_freq_response(rig, reply, sizeof(reply), __func__) < 0) {
+            RETURN_CACHED_FREQ(rig, vfo, freq);
+        }
+
+        // Parse frequency (big-endian)
+        int freq_a_offset = 9;  // VFOA frequency starting position
+        int freq_b_offset = 13; // VFOB frequency starting position
+
+        uint32_t freq_a = (reply[freq_a_offset] << 24) | 
+                         (reply[freq_a_offset+1] << 16) | 
+                         (reply[freq_a_offset+2] << 8) | 
+                         reply[freq_a_offset+3];
+
+        uint32_t freq_b = (reply[freq_b_offset] << 24) | 
+                         (reply[freq_b_offset+1] << 16) | 
+                         (reply[freq_b_offset+2] << 8) | 
+                         reply[freq_b_offset+3];
+
+        // Update cache
+        CACHE(rig)->freqMainA = (freq_t)freq_a;
+        CACHE(rig)->freqMainB = (freq_t)freq_b;
+
+        // Return requested VFO frequency
+        *freq = (vfo == RIG_VFO_A) ? CACHE(rig)->freqMainA : CACHE(rig)->freqMainB;
+
+        rig_debug(RIG_DEBUG_VERBOSE, "%s: Successfully got VFOA=%.0f Hz, VFOB=%.0f Hz\n",
+                 __func__, CACHE(rig)->freqMainA, CACHE(rig)->freqMainB);
     }
-
-    // Parse frequency (big-endian)
-    int freq_a_offset = 9;  // VFOA frequency starting position
-    int freq_b_offset = 13; // VFOB frequency starting position
-
-    uint32_t freq_a = (reply[freq_a_offset] << 24) | 
-                     (reply[freq_a_offset+1] << 16) | 
-                     (reply[freq_a_offset+2] << 8) | 
-                     reply[freq_a_offset+3];
-
-    uint32_t freq_b = (reply[freq_b_offset] << 24) | 
-                     (reply[freq_b_offset+1] << 16) | 
-                     (reply[freq_b_offset+2] << 8) | 
-                     reply[freq_b_offset+3];
-
-    // Update cache
-    CACHE(rig)->freqMainA = (freq_t)freq_a;
-    CACHE(rig)->freqMainB = (freq_t)freq_b;
-
-    // Return requested VFO frequency
-    *freq = (vfo == RIG_VFO_A) ? CACHE(rig)->freqMainA : CACHE(rig)->freqMainB;
-
-    rig_debug(RIG_DEBUG_VERBOSE, "%s: Successfully got VFOA=%.0f Hz, VFOB=%.0f Hz\n",
-             __func__, CACHE(rig)->freqMainA, CACHE(rig)->freqMainB);
-
     return RIG_OK;
  }
  
@@ -407,28 +407,25 @@ static int pmr171_open(RIG *rig)
  {
     struct rig_cache *cachep = CACHE(rig);
     const pmr171_data_t *p = (pmr171_data_t *) STATE(rig)->priv;
-    unsigned char reply[40];
-     
-    // Get latest status from hardware
-    pmr171_send_cmd1(rig, 0x0b, 0);
-    
-    // Read and validate response using common function
-    if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
-        RETURN_CACHED_MODE(rig, vfo, mode, width, cachep, p);
+    {
+        unsigned char reply[40];
+        // Get latest status from hardware
+        pmr171_send_cmd1(rig, 0x0b, 0);
+        // Read and validate response using common function
+        if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
+            RETURN_CACHED_MODE(rig, vfo, mode, width, cachep, p);
+        }
+        // Validate mode response using common function
+        if (validate_mode_response(rig, reply, sizeof(reply), __func__, 5) < 0) {
+            RETURN_CACHED_MODE(rig, vfo, mode, width, cachep, p);
+        }
+        // Update cache
+        cachep->modeMainA = guohe2rmode(reply[7], pmr171_modes);
+        cachep->modeMainB = guohe2rmode(reply[8], pmr171_modes);
+        // Return requested mode
+        *mode = (vfo == RIG_VFO_A) ? cachep->modeMainA : cachep->modeMainB;
+        *width = p->filterBW;
     }
-
-    // Validate mode response using common function
-    if (validate_mode_response(rig, reply, sizeof(reply), __func__, 5) < 0) {
-        RETURN_CACHED_MODE(rig, vfo, mode, width, cachep, p);
-    }
-
-    // Update cache
-    cachep->modeMainA = guohe2rmode(reply[7], pmr171_modes);
-    cachep->modeMainB = guohe2rmode(reply[8], pmr171_modes);
-
-    // Return requested mode
-    *mode = (vfo == RIG_VFO_A) ? cachep->modeMainA : cachep->modeMainB;
-    *width = p->filterBW;
     return RIG_OK;
  }
  
@@ -445,25 +442,22 @@ static int pmr171_open(RIG *rig)
 
  static int pmr171_get_vfo(RIG *rig, vfo_t *vfo)
  {
-    unsigned char reply[40];
-    
-    // Send status sync command to get current VFO state
-    pmr171_send_cmd1(rig, 0x0b, 0);
-    
-    // Read and validate response using common function
-    if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
-        RETURN_CACHED_VFO(rig, vfo);
+    {
+        unsigned char reply[40];
+        // Send status sync command to get current VFO state
+        pmr171_send_cmd1(rig, 0x0b, 0);
+        // Read and validate response using common function
+        if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
+            RETURN_CACHED_VFO(rig, vfo);
+        }
+        // Validate VFO status field index won't overflow
+        if (reply[4] < 13) { // Need at least 13 bytes to access reply[17]
+            rig_debug(RIG_DEBUG_ERR, "%s: Response too short for VFO data, using cached values\n", __func__);
+            RETURN_CACHED_VFO(rig, vfo);
+        }
+        // According to protocol doc, reply[17] is A/B frequency status
+        *vfo = (reply[17] == 1) ? RIG_VFO_B : RIG_VFO_A;
     }
-    
-    // Validate VFO status field index won't overflow
-    if (reply[4] < 13) { // Need at least 13 bytes to access reply[17]
-        rig_debug(RIG_DEBUG_ERR, "%s: Response too short for VFO data, using cached values\n", __func__);
-        RETURN_CACHED_VFO(rig, vfo);
-    }
-    
-    // According to protocol doc, reply[17] is A/B frequency status
-    *vfo = (reply[17] == 1) ? RIG_VFO_B : RIG_VFO_A;
-    
     return RIG_OK;
  }
 
@@ -471,25 +465,22 @@ static int pmr171_open(RIG *rig)
  static int pmr171_get_ptt(RIG *rig, vfo_t vfo, ptt_t *ptt)
  {
     struct rig_cache *cachep = CACHE(rig);
-    unsigned char reply[40];
-
-    pmr171_send_cmd1(rig, 0x0b, 0);
-    
-    // Read and validate response using common function
-    if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
-        RETURN_CACHED_PTT(rig, ptt, cachep);
+    {
+        unsigned char reply[40];
+        pmr171_send_cmd1(rig, 0x0b, 0);
+        // Read and validate response using common function
+        if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
+            RETURN_CACHED_PTT(rig, ptt, cachep);
+        }
+        // Validate PTT status field index won't overflow
+        if (reply[4] < 2) { // Need at least 2 bytes to access reply[6]
+            rig_debug(RIG_DEBUG_ERR, "%s: Response too short for PTT data, using cached values\n", __func__);
+            RETURN_CACHED_PTT(rig, ptt, cachep);
+        }
+        // Get PTT status
+        cachep->ptt = reply[6];
+        *ptt = cachep->ptt;
     }
-
-    // Validate PTT status field index won't overflow
-    if (reply[4] < 2) { // Need at least 2 bytes to access reply[6]
-        rig_debug(RIG_DEBUG_ERR, "%s: Response too short for PTT data, using cached values\n", __func__);
-        RETURN_CACHED_PTT(rig, ptt, cachep);
-    }
-
-    // Get PTT status
-    cachep->ptt = reply[6];
-    *ptt = cachep->ptt;
-
     return RIG_OK;
  }
  
@@ -525,28 +516,24 @@ static int pmr171_open(RIG *rig)
  static int pmr171_send_cmd2(RIG *rig, unsigned char cmd, unsigned char value,
                              int response)
  {
-     unsigned char reply[40];
+     unsigned char buf[64] = { 0xa5, 0xa5, 0xa5, 0xa5, 0x04, 0x00, 0x00, 0x00, 0x00 };
      hamlib_port_t *rp = RIGPORT(rig);
      rig_debug(RIG_DEBUG_VERBOSE, "%s: called\n", __func__);
-     unsigned char buf[64] = { 0xa5, 0xa5, 0xa5, 0xa5, 0x04, 0x00, 0x00, 0x00, 0x00 };
-
      buf[5] = cmd;
      buf[6] = value;
      unsigned int crc = CRC16Check(&buf[4], 3);
      buf[7] = crc >> 8;
      buf[8] = crc & 0xff;
-
      rig_flush(rp);
      write_block(rp, buf, 9);
-
      if (response)
      {
+         unsigned char reply[40];
          // Use common response reading function
          if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
              return RIG_OK; // Return OK to use cached values
          }
      }
-
      return pmr171_read_ack(rig);
  }
  
diff --git a/rigs/guohetec/q900.c b/rigs/guohetec/q900.c
index 059106f67..2e6d6bc0e 100644
--- a/rigs/guohetec/q900.c
+++ b/rigs/guohetec/q900.c
@@ -363,36 +363,32 @@ static int q900_get_freq(RIG *rig, vfo_t vfo, freq_t *freq)
     cmd[6] = crc >> 8;
     cmd[7] = crc & 0xFF;
 
-    unsigned char reply[40];
-    q900_send(rig, cmd, sizeof(cmd), reply, sizeof(reply));
-
-    // Validate response using common function
-    if (validate_freq_response(rig, reply, sizeof(reply), __func__) < 0) {
-        RETURN_CACHED_FREQ(rig, vfo, freq);
+    {
+        unsigned char reply[40];
+        q900_send(rig, cmd, sizeof(cmd), reply, sizeof(reply));
+        // Validate response using common function
+        if (validate_freq_response(rig, reply, sizeof(reply), __func__) < 0) {
+            RETURN_CACHED_FREQ(rig, vfo, freq);
+        }
+        // Parse frequency (big-endian)
+        int freq_a_offset = 9;  // VFOA frequency starting position
+        int freq_b_offset = 13; // VFOB frequency starting position
+        uint32_t freq_a = (reply[freq_a_offset] << 24) | 
+                         (reply[freq_a_offset+1] << 16) | 
+                         (reply[freq_a_offset+2] << 8) | 
+                         reply[freq_a_offset+3];
+        uint32_t freq_b = (reply[freq_b_offset] << 24) | 
+                         (reply[freq_b_offset+1] << 16) | 
+                         (reply[freq_b_offset+2] << 8) | 
+                         reply[freq_b_offset+3];
+        // Update cache
+        CACHE(rig)->freqMainA = (freq_t)freq_a;
+        CACHE(rig)->freqMainB = (freq_t)freq_b;
+        // Return requested VFO frequency
+        *freq = (vfo == RIG_VFO_A) ? CACHE(rig)->freqMainA : CACHE(rig)->freqMainB;
+        rig_debug(RIG_DEBUG_VERBOSE, "%s: Successfully got VFOA=%.0f Hz, VFOB=%.0f Hz\n",
+                 __func__, CACHE(rig)->freqMainA, CACHE(rig)->freqMainB);
     }
-
-    // Parse frequency (big-endian)
-    int freq_a_offset = 9; 
-    int freq_b_offset = 13; 
-
-    uint32_t freq_a = (reply[freq_a_offset] << 24) | 
-                     (reply[freq_a_offset+1] << 16) | 
-                     (reply[freq_a_offset+2] << 8) | 
-                     reply[freq_a_offset+3];
-
-    uint32_t freq_b = (reply[freq_b_offset] << 24) | 
-                     (reply[freq_b_offset+1] << 16) | 
-                     (reply[freq_b_offset+2] << 8) | 
-                     reply[freq_b_offset+3];
-
-    CACHE(rig)->freqMainA = (freq_t)freq_a;
-    CACHE(rig)->freqMainB = (freq_t)freq_b;
-
-    *freq = (vfo == RIG_VFO_A) ? CACHE(rig)->freqMainA : CACHE(rig)->freqMainB;
-
-    rig_debug(RIG_DEBUG_VERBOSE, "%s: Successfully obtained VFOA=%.0f Hz, VFOB=%.0f Hz\n",
-             __func__, CACHE(rig)->freqMainA, CACHE(rig)->freqMainB);
-
     return RIG_OK;
 }
  
@@ -400,25 +396,25 @@ static int q900_get_freq(RIG *rig, vfo_t vfo, freq_t *freq)
  {
     struct rig_cache *cachep = CACHE(rig);
     const q900_data_t *p = (q900_data_t *) STATE(rig)->priv;
-    unsigned char reply[255];
-     
-    q900_send_cmd1(rig, 0x0b, 0);
-    
-    // Read and validate response using common function
-    if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
-        RETURN_CACHED_MODE(rig, vfo, mode, width, cachep, p);
+    {
+        unsigned char reply[255];
+        // Get latest status from hardware
+        q900_send_cmd1(rig, 0x0b, 0);
+        // Read and validate response using common function
+        if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
+            RETURN_CACHED_MODE(rig, vfo, mode, width, cachep, p);
+        }
+        // Validate mode response using common function
+        if (validate_mode_response(rig, reply, sizeof(reply), __func__, 5) < 0) {
+            RETURN_CACHED_MODE(rig, vfo, mode, width, cachep, p);
+        }
+        // Update cache
+        cachep->modeMainA = guohe2rmode(reply[7], q900_modes);
+        cachep->modeMainB = guohe2rmode(reply[8], q900_modes);
+        // Return requested mode
+        *mode = (vfo == RIG_VFO_A) ? cachep->modeMainA : cachep->modeMainB;
+        *width = p->filterBW;
     }
-
-    // Validate mode response using common function
-    if (validate_mode_response(rig, reply, sizeof(reply), __func__, 5) < 0) {
-        RETURN_CACHED_MODE(rig, vfo, mode, width, cachep, p);
-    }
-
-    cachep->modeMainA = guohe2rmode(reply[7], q900_modes);
-    cachep->modeMainB = guohe2rmode(reply[8], q900_modes);
-
-    *mode = (vfo == RIG_VFO_A) ? cachep->modeMainA : cachep->modeMainB;
-    *width = p->filterBW;
     return RIG_OK;
  }
  
@@ -435,29 +431,22 @@ static int q900_get_freq(RIG *rig, vfo_t vfo, freq_t *freq)
 
  static int q900_get_vfo(RIG *rig, vfo_t *vfo)
  {
-    unsigned char reply[255];
-    
-    q900_send_cmd1(rig, 0x0b, 0);
-    
-    // Read and validate response using common function
-    if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
-        RETURN_CACHED_VFO(rig, vfo);
+    {
+        unsigned char reply[255];
+        // Send status sync command to get current VFO state
+        q900_send_cmd1(rig, 0x0b, 0);
+        // Read and validate response using common function
+        if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
+            RETURN_CACHED_VFO(rig, vfo);
+        }
+        // Validate VFO status field index won't overflow
+        if (reply[4] < 13) { // Need at least 13 bytes to access reply[17]
+            rig_debug(RIG_DEBUG_ERR, "%s: Response too short for VFO data, using cached values\n", __func__);
+            RETURN_CACHED_VFO(rig, vfo);
+        }
+        // According to protocol doc, reply[17] is A/B frequency status
+        *vfo = (reply[17] == 1) ? RIG_VFO_B : RIG_VFO_A;
     }
-    
-    // Validate VFO status field index won't overflow
-    if (reply[4] < 13) { // Need at least 13 bytes to access reply[17]
-        rig_debug(RIG_DEBUG_ERR, "%s: Response too short for VFO data, using cached values\n", __func__);
-        RETURN_CACHED_VFO(rig, vfo);
-    }
-    
-    // Validate VFO status value
-    if (reply[17] != 0 && reply[17] != 1) {
-        rig_debug(RIG_DEBUG_ERR, "%s: Invalid VFO status value %d, using cached values\n", __func__, reply[17]);
-        RETURN_CACHED_VFO(rig, vfo);
-    }
-    
-    *vfo = (reply[17] == 1) ? RIG_VFO_B : RIG_VFO_A;
-    
     return RIG_OK;
  }
 
@@ -465,30 +454,22 @@ static int q900_get_freq(RIG *rig, vfo_t vfo, freq_t *freq)
 static int q900_get_ptt(RIG *rig, vfo_t vfo, ptt_t *ptt)
 {
     struct rig_cache *cachep = CACHE(rig);
-    unsigned char reply[255];
-
-    q900_send_cmd1(rig, 0x0b, 0);
-    
-    // Read and validate response using common function
-    if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
-        RETURN_CACHED_PTT(rig, ptt, cachep);
+    {
+        unsigned char reply[255];
+        q900_send_cmd1(rig, 0x0b, 0);
+        // Read and validate response using common function
+        if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
+            RETURN_CACHED_PTT(rig, ptt, cachep);
+        }
+        // Validate PTT status field index won't overflow
+        if (reply[4] < 2) { // Need at least 2 bytes to access reply[6]
+            rig_debug(RIG_DEBUG_ERR, "%s: Response too short for PTT data, using cached values\n", __func__);
+            RETURN_CACHED_PTT(rig, ptt, cachep);
+        }
+        // Get PTT status
+        cachep->ptt = reply[6];
+        *ptt = cachep->ptt;
     }
-
-    // Validate PTT status field index won't overflow
-    if (reply[4] < 2) { // Need at least 2 bytes to access reply[6]
-        rig_debug(RIG_DEBUG_ERR, "%s: Response too short for PTT data, using cached values\n", __func__);
-        RETURN_CACHED_PTT(rig, ptt, cachep);
-    }
-
-    // Validate PTT status value
-    if (reply[6] != 0 && reply[6] != 1) {
-        rig_debug(RIG_DEBUG_ERR, "%s: Invalid PTT status value %d, using cached values\n", __func__, reply[6]);
-        RETURN_CACHED_PTT(rig, ptt, cachep);
-    }
-
-    cachep->ptt = reply[6];
-    *ptt = cachep->ptt;
-
     return RIG_OK;
 }
  
@@ -527,28 +508,24 @@ static int q900_get_ptt(RIG *rig, vfo_t vfo, ptt_t *ptt)
  static int q900_send_cmd2(RIG *rig, unsigned char cmd, unsigned char value,
                              int response)
  {
-     unsigned char reply[256];
+     unsigned char buf[64] = { 0xa5, 0xa5, 0xa5, 0xa5, 0x04, 0x00, 0x00, 0x00, 0x00 };
      hamlib_port_t *rp = RIGPORT(rig);
      rig_debug(RIG_DEBUG_VERBOSE, "%s: called\n", __func__);
-     unsigned char buf[64] = { 0xa5, 0xa5, 0xa5, 0xa5, 0x04, 0x00, 0x00, 0x00, 0x00 };
-
      buf[5] = cmd;
      buf[6] = value;
      unsigned int crc = CRC16Check(&buf[4], 3);
      buf[7] = crc >> 8;
      buf[8] = crc & 0xff;
-
      rig_flush(rp);
      write_block(rp, buf, 9);
-
      if (response)
      {
+         unsigned char reply[256];
          // Use common response reading function
          if (read_rig_response(rig, reply, sizeof(reply), __func__) < 0) {
              return RIG_OK; // Return OK to use cached values
          }
      }
-
      return q900_read_ack(rig);
  }