diff --git a/src/mesh/STM32WLE5JCInterface.cpp b/src/mesh/STM32WLE5JCInterface.cpp
index f6e4b3512a2..567cd4c00f0 100644
--- a/src/mesh/STM32WLE5JCInterface.cpp
+++ b/src/mesh/STM32WLE5JCInterface.cpp
@@ -19,8 +19,8 @@ bool STM32WLE5JCInterface::init()
     RadioLibInterface::init();
 
 // https://github.com/Seeed-Studio/LoRaWan-E5-Node/blob/main/Middlewares/Third_Party/SubGHz_Phy/stm32_radio_driver/radio_driver.c
-#if (!defined(_VARIANT_RAK3172_))
-    setTCXOVoltage(1.7);
+#if defined(SX126X_DIO3_TCXO_VOLTAGE)
+    setTCXOVoltage(SX126X_DIO3_TCXO_VOLTAGE);
 #endif
 
     lora.setRfSwitchTable(rfswitch_pins, rfswitch_table);
@@ -29,6 +29,17 @@ bool STM32WLE5JCInterface::init()
 
     int res = lora.begin(getFreq(), bw, sf, cr, syncWord, power, preambleLength, tcxoVoltage);
 
+#if defined(TCXO_OPTIONAL)
+    // If a TCXO was requested but isn't actually populated (e.g. non-T RAK3172), retry on XTAL
+    if (res != RADIOLIB_ERR_NONE && res != RADIOLIB_ERR_CHIP_NOT_FOUND && tcxoVoltage > 0) {
+        LOG_WARN("STM32WLx init failed with TCXO Vref %fV (err %d), retrying without TCXO", tcxoVoltage, res);
+        setTCXOVoltage(0);
+        res = lora.begin(getFreq(), bw, sf, cr, syncWord, power, preambleLength, tcxoVoltage);
+        if (res == RADIOLIB_ERR_NONE)
+            LOG_INFO("STM32WLx init success without TCXO (XTAL mode)");
+    }
+#endif
+
     LOG_INFO("STM32WLx init result %d", res);
 
     LOG_INFO("Frequency set to %f", getFreq());
diff --git a/variants/stm32/CDEBYTE_E77-MBL/variant.h b/variants/stm32/CDEBYTE_E77-MBL/variant.h
index 686326137a7..b2f84f23536 100644
--- a/variants/stm32/CDEBYTE_E77-MBL/variant.h
+++ b/variants/stm32/CDEBYTE_E77-MBL/variant.h
@@ -22,4 +22,11 @@ Do not expect a working Meshtastic device with this target.
 #define SERIAL_PRINT_PORT 1
 
 #define EBYTE_E77_MBL
+
+// LoRa
+// Hardware varies by unit: SN >= 3202995 has a TCXO, older units have XTAL only -
+// https://github.com/olliw42/mLRS-docu/blob/main/docs/EBYTE_E77_MBL.md
+#define TCXO_OPTIONAL
+#define SX126X_DIO3_TCXO_VOLTAGE 1.7
+
 #endif
diff --git a/variants/stm32/rak3172/variant.h b/variants/stm32/rak3172/variant.h
index 75e3e0c919e..4d718333789 100644
--- a/variants/stm32/rak3172/variant.h
+++ b/variants/stm32/rak3172/variant.h
@@ -24,4 +24,10 @@ Do not expect a working Meshtastic device with this target.
 #define RAK3172
 #define SERIAL_PRINT_PORT 1
 
+// LoRa
+// RAK3172: no TCXO, RAK3172-T: 3.0V TCXO -
+// https://github.com/RAKWireless/RAK-STM32-RUI/blob/e5a28be8fab1a492bd9223dd425ca33a8a297d90/variants/WisDuo_RAK3172-T_Board/radio_conf.h#L91
+#define TCXO_OPTIONAL
+#define SX126X_DIO3_TCXO_VOLTAGE 3.0
+
 #endif
diff --git a/variants/stm32/wio-e5/variant.h b/variants/stm32/wio-e5/variant.h
index da2c623fb3b..ad733ff5f49 100644
--- a/variants/stm32/wio-e5/variant.h
+++ b/variants/stm32/wio-e5/variant.h
@@ -19,4 +19,8 @@ Do not expect a working Meshtastic device with this target.
 
 #define WIO_E5
 
+// LoRa
+// https://github.com/Seeed-Studio/LoRaWan-E5-Node/blob/163c05379b1805dd8f2c061d4557a69985acc953/Middlewares/Third_Party/SubGHz_Phy/stm32_radio_driver/radio_driver.c#L94
+#define SX126X_DIO3_TCXO_VOLTAGE 1.7
+
 #endif