macOS: GPU temperature not displayed on Apple Silicon M5 (SMC `flt ` data type not parsed)

long long SMCConnection::getSMCTemp(char *key) {
    SMCVal_t val;
    kern_return_t result;
    result = SMCReadKey(key, &val);
    if (result != kIOReturnSuccess or val.dataSize == 0) return -1;

    // sp78: 8-bit signed integer + 8-bit fraction (Intel Mac legacy)
    if (strcmp(val.dataType, DATATYPE_SP78) == 0) {
        int intValue = val.bytes[0] * 256 + (unsigned char)val.bytes[1];
        return static_cast<long long>(intValue / 256.0);
    }
    // flt : 4-byte IEEE little-endian float (Apple Silicon GPU/temp sensors)
    if (strcmp(val.dataType, "flt ") == 0 and val.dataSize >= 4) {
        float f;
        memcpy(&f, val.bytes, sizeof(f));
        if (f > 0.0f and f < 150.0f) {
            return static_cast<long long>(f + 0.5f);
        }
    }
    // ui16: rare for temperature, included for completeness
    if (strcmp(val.dataType, "ui16") == 0 and val.dataSize >= 2) {
        unsigned int u = ((unsigned char)val.bytes[0] << 8) | (unsigned char)val.bytes[1];
        if (u > 0 and u < 150) return static_cast<long long>(u);
    }
    return -1;
}

// in smc.hpp public section
long long getTempByKey(const char *key);

// in smc.cpp
long long SMCConnection::getTempByKey(const char *key) {
    char k[5];
    strncpy(k, key, 4);
    k[4] = '\0';
    long long t = getSMCTemp(k);
    if (t <= 0 or t >= 150) return -1;
    return t;
}

// added before get_gpu_temp_iohid()
static long long get_gpu_temp_smc() {
    static const char* keys_all[] = {
        // M5
        "Tg0U", "Tg0X", "Tg0d", "Tg0g", "Tg0j", "Tg1Y", "Tg1c", "Tg1g",
        // M4
        "Tg0G", "Tg0H", "Tg1U", "Tg1k", "Tg0K", "Tg0L", "Tg0e", "Tg0k",
        // M2
        "Tg0f", "Tg0j",
        // M1
        "Tg05", "Tg0D", "Tg0L", "Tg0T",
        nullptr,
    };
    try {
        Cpu::SMCConnection smc;
        double sum = 0;
        int count = 0;
        for (size_t i = 0; keys_all[i] != nullptr; ++i) {
            long long t = smc.getTempByKey(keys_all[i]);
            if (t > 0 and t < 150) {
                sum += static_cast<double>(t);
                count++;
            }
        }
        if (count > 0) {
            return static_cast<long long>(round(sum / count));
        }
    } catch (...) {}
    return -1;
}

// at the GPU temperature collection site
if (gpus_slice[0].supported_functions.temp_info and Config::getB("check_temp")) {
    long long temp = get_gpu_temp_smc();
    if (temp <= 0)
        temp = get_gpu_temp_iohid();
    if (temp > 0)
        gpus_slice[0].temp.push_back(temp);
}

diff --git a/src/osx/btop_collect.cpp b/src/osx/btop_collect.cpp
index ed8a3d2..7bdb286 100644
--- a/src/osx/btop_collect.cpp
+++ b/src/osx/btop_collect.cpp
@@ -339,6 +339,42 @@ namespace Gpu {
 			return true;
 		}
 
+		//? Read GPU temperature via SMC using chip-specific sensor keys.
+		//? Apple Silicon exposes GPU thermal sensors as 4-character SMC keys.
+		//? Key sets change per chip generation. Lists below are from exelban/stats
+		//? (Modules/Sensors/values.swift), which is actively maintained per M-series chip.
+		static long long get_gpu_temp_smc() {
+			static const char* keys_all[] = {
+				// M5
+				"Tg0U", "Tg0X", "Tg0d", "Tg0g", "Tg0j", "Tg1Y", "Tg1c", "Tg1g",
+				// M4 (base + Pro/Max/Ultra)
+				"Tg0G", "Tg0H", "Tg1U", "Tg1k", "Tg0K", "Tg0L", "Tg0e", "Tg0k",
+				// M2
+				"Tg0f", "Tg0j",
+				// M1
+				"Tg05", "Tg0D", "Tg0L", "Tg0T",
+				nullptr,
+			};
+			try {
+				Cpu::SMCConnection smc;
+				double sum = 0;
+				int count = 0;
+				for (size_t i = 0; keys_all[i] != nullptr; ++i) {
+					long long t = smc.getTempByKey(keys_all[i]);
+					if (t > 0 and t < 150) {
+						sum += static_cast<double>(t);
+						count++;
+					}
+				}
+				if (count > 0) {
+					return static_cast<long long>(round(sum / count));
+				}
+			} catch (...) {
+				// SMC unavailable; fall through
+			}
+			return -1;
+		}
+
 		//? Read GPU temperature via IOHIDEventSystem thermal sensors
 		static long long get_gpu_temp_iohid() {
 			#if __MAC_OS_X_VERSION_MIN_REQUIRED > 101504
@@ -546,9 +582,12 @@ namespace Gpu {
 					clamp(static_cast<long long>(round(static_cast<double>(gpus_slice[0].pwr_usage) * 100.0 / static_cast<double>(gpus_slice[0].pwr_max_usage))), 0ll, 100ll));
 			}
 
-			//? GPU temperature
+			//? GPU temperature — try SMC first (chip-specific sensor keys; works on M5+
+			//? where IOHID exposes only generic die probes), then IOHID fallback.
 			if (gpus_slice[0].supported_functions.temp_info and Config::getB("check_temp")) {
-				long long temp = get_gpu_temp_iohid();
+				long long temp = get_gpu_temp_smc();
+				if (temp <= 0)
+					temp = get_gpu_temp_iohid();
 				if (temp > 0)
 					gpus_slice[0].temp.push_back(temp);
 			}
diff --git a/src/osx/smc.cpp b/src/osx/smc.cpp
index cddf6de..94df964 100644
--- a/src/osx/smc.cpp
+++ b/src/osx/smc.cpp
@@ -73,18 +73,41 @@ namespace Cpu {
 		SMCVal_t val;
 		kern_return_t result;
 		result = SMCReadKey(key, &val);
-		if (result == kIOReturnSuccess) {
-			if (val.dataSize > 0) {
-				if (strcmp(val.dataType, DATATYPE_SP78) == 0) {
-					// convert sp78 value to temperature
-					int intValue = val.bytes[0] * 256 + (unsigned char)val.bytes[1];
-					return static_cast<long long>(intValue / 256.0);
-				}
+		if (result != kIOReturnSuccess or val.dataSize == 0) return -1;
+
+		// sp78: 8-bit signed integer + 8-bit fraction (Intel Mac legacy)
+		if (strcmp(val.dataType, DATATYPE_SP78) == 0) {
+			int intValue = val.bytes[0] * 256 + (unsigned char)val.bytes[1];
+			return static_cast<long long>(intValue / 256.0);
+		}
+		// flt : 4-byte IEEE little-endian float (Apple Silicon GPU/temp sensors)
+		if (strcmp(val.dataType, "flt ") == 0 and val.dataSize >= 4) {
+			float f;
+			memcpy(&f, val.bytes, sizeof(f));
+			if (f > 0.0f and f < 150.0f) {
+				return static_cast<long long>(f + 0.5f);
 			}
 		}
+		// ui16 / fpe2: rare for temperature on Apple Silicon but seen historically
+		if (strcmp(val.dataType, "ui16") == 0 and val.dataSize >= 2) {
+			unsigned int u = ((unsigned char)val.bytes[0] << 8) | (unsigned char)val.bytes[1];
+			if (u > 0 and u < 150) return static_cast<long long>(u);
+		}
 		return -1;
 	}
 
+	// Read an arbitrary 4-char SMC key (e.g., "Tg0U" for M5 GPU sensor 1).
+	// Returns the temperature in °C as an integer, or -1 if the key is unsupported
+	// or the value is out of plausible range.
+	long long SMCConnection::getTempByKey(const char *key) {
+		char k[5];
+		strncpy(k, key, 4);
+		k[4] = '\0';
+		long long t = getSMCTemp(k);
+		if (t <= 0 or t >= 150) return -1;
+		return t;
+	}
+
 	// core means physical core in SMC, while in core map it's cpu threads :-/ Only an issue on hackintosh?
 	// this means we can only get the T per physical core
 	// another issue with the SMC API is that the key is always 4 chars -> what with systems with more than 9 physical cores?
diff --git a/src/osx/smc.hpp b/src/osx/smc.hpp
index 5717b64..a98ead7 100644
--- a/src/osx/smc.hpp
+++ b/src/osx/smc.hpp
@@ -102,6 +102,9 @@ namespace Cpu {
 		virtual ~SMCConnection();
 
 		long long getTemp(int core);
+		// Read an arbitrary 4-character SMC key as a temperature in °C.
+		// Returns -1 on failure or unsupported key.
+		long long getTempByKey(const char *key);
 
 	   private:
 		kern_return_t SMCReadKey(UInt32Char_t key, SMCVal_t *val);