diff --git a/code/espurna/sensors/PZEM004TSensor.h b/code/espurna/sensors/PZEM004TSensor.h
index 8dd0e600..e18ea94f 100644
--- a/code/espurna/sensors/PZEM004TSensor.h
+++ b/code/espurna/sensors/PZEM004TSensor.h
@@ -287,16 +287,26 @@ public:
     static constexpr size_t DevicesMax { PZEM004T_DEVICES_MAX };
 
     static IPAddress defaultAddress(size_t device) {
-        const __FlashStringHelper* ptr {
-            (0 == device) ? F(PZEM004T_ADDRESS_1) :
-            (1 == device) ? F(PZEM004T_ADDRESS_2) :
-            (2 == device) ? F(PZEM004T_ADDRESS_3) :
-            (3 == device) ? F(PZEM004T_ADDRESS_4) :
-            nullptr
+        static const espurna::StringView addresses[] PROGMEM {
+#define PZEM004T_MAKE_ADDRESS(X)\
+        (__extension__({\
+            STRING_VIEW_INLINE(Address, X);\
+            Address;}))
+
+            PZEM004T_MAKE_ADDRESS(PZEM004T_ADDRESS_1),
+            PZEM004T_MAKE_ADDRESS(PZEM004T_ADDRESS_2),
+            PZEM004T_MAKE_ADDRESS(PZEM004T_ADDRESS_3),
+            PZEM004T_MAKE_ADDRESS(PZEM004T_ADDRESS_4),
+
+#undef PZEM004T_MAKE_ADDRESS
         };
 
         IPAddress out;
-        out.fromString(String(ptr));
+        if (device < std::size(addresses)) {
+            out.fromString(addresses[device].toString());
+        } else {
+            out.fromString(nullptr);
+        }
 
         return out;
     }
diff --git a/code/espurna/sensors/PZEM004TV30Sensor.h b/code/espurna/sensors/PZEM004TV30Sensor.h
index b222bbee..521ededa 100644
--- a/code/espurna/sensors/PZEM004TV30Sensor.h
+++ b/code/espurna/sensors/PZEM004TV30Sensor.h
@@ -176,9 +176,10 @@ public:
         bool locked { false };
     };
 
-    void modbusDebugBuffer(const String& message, buffer_type& buffer, size_t size) {
+    void modbusDebugBuffer(espurna::StringView message, buffer_type& buffer, size_t size) {
         hexEncode(buffer.data(), size, _debug_buffer, sizeof(_debug_buffer));
-        PZEM_DEBUG_MSG_P(PSTR("[PZEM004TV3] %s: %s (%u bytes)\n"), message.c_str(), _debug_buffer, size);
+        PZEM_DEBUG_MSG_P(PSTR("[PZEM004TV3] %.*s: %s (%u bytes)\n"),
+            message.length(), message.data(), _debug_buffer, size);
     }
 
     static size_t modbusExpect(const adu_builder& builder) {
@@ -250,7 +251,7 @@ public:
         }
 
         if (bytes && _debug) {
-            modbusDebugBuffer(F("Received"), buffer, bytes);
+            modbusDebugBuffer(STRING_VIEW("Received"), buffer, bytes);
         }
 
         if (bytes != expect) {
@@ -269,7 +270,7 @@ public:
 
         if (buffer[1] & ErrorMask) {
             PZEM_DEBUG_MSG_P(PSTR("[PZEM004TV3] ERROR: %s (0x%02X)\n"),
-                errorToString(buffer[2]).c_str(), buffer[2]);
+                errorToString(buffer[2]).toString().c_str(), buffer[2]);
             return;
         }
 
@@ -312,36 +313,37 @@ public:
     }
 
     // For more, see MODBUS application protocol specification, 7 MODBUS Exception Responses
-    String errorToString(uint8_t error) {
-        const __FlashStringHelper *ptr = nullptr;
+    espurna::StringView errorToString(uint8_t error) {
+        espurna::StringView out;
+
         switch (error) {
         case 0x01:
-            ptr = F("Illegal function");
+            out = STRING_VIEW("Illegal function");
             break;
         case 0x02:
-            ptr = F("Illegal data address");
+            out = STRING_VIEW("Illegal data address");
             break;
         case 0x03:
-            ptr = F("Illegal data value");
+            out = STRING_VIEW("Illegal data value");
             break;
         case 0x04:
-            ptr = F("Device failure");
+            out = STRING_VIEW("Device failure");
             break;
         case 0x05:
-            ptr = F("Acknowledged");
+            out = STRING_VIEW("Acknowledged");
             break;
         case 0x06:
-            ptr = F("Busy");
+            out = STRING_VIEW("Busy");
             break;
         case 0x08:
-            ptr = F("Memory parity error");
+            out = STRING_VIEW("Memory parity error");
             break;
         default:
-            ptr = F("Unknown");
+            out = STRING_VIEW("Unknown");
             break;
         }
 
-        return ptr;
+        return out;
     }
 
     // Quoting the README.md of the original library repo and datasheet, we have:
@@ -510,8 +512,8 @@ public:
     }
 
     String description() const override {
-        static const String base(F("PZEM004TV30"));
-        return base + " @ 0x" + String(_address, 16);
+        STRING_VIEW_INLINE(Base, "PZEM004TV30 @ 0x");
+        return Base + String(_address, 16);
     }
 
     String address(unsigned char) const override {
@@ -603,11 +605,11 @@ constexpr espurna::duration::Milliseconds PZEM004TV30Sensor::DefaultUpdateInterv
 
 PZEM004TV30Sensor::Instance PZEM004TV30Sensor::_instance{};
 
-PROGMEM_STRING(PzemV3Address, "PZ.ADDRESS");
+STRING_VIEW_INLINE(PzemV3Address, "PZ.ADDRESS");
 
 void PZEM004TV30Sensor::command_address(::terminal::CommandContext&& ctx) {
     if (ctx.argv.size() != 2) {
-        terminalError(ctx, F("PZ.ADDRESS <ADDRESS>"));
+        terminalError(ctx, STRING_VIEW("PZ.ADDRESS <ADDRESS>"));
         return;
     }
 
@@ -621,7 +623,7 @@ void PZEM004TV30Sensor::command_address(::terminal::CommandContext&& ctx) {
         return;
     }
 
-    terminalError(ctx, F("Could not change the address"));
+    terminalError(ctx, STRING_VIEW("Could not change the address"));
 }
 
 static constexpr ::terminal::Command PzemV3Commands[] PROGMEM {