diff --git a/radio/src/boards/generic_stm32/module_ports.cpp b/radio/src/boards/generic_stm32/module_ports.cpp
index 4eca95a9c..f9a0acc69 100644
--- a/radio/src/boards/generic_stm32/module_ports.cpp
+++ b/radio/src/boards/generic_stm32/module_ports.cpp
@@ -293,9 +293,15 @@ static const stm32_usart_t sportUSART = {
   .txDMA = TELEMETRY_DMA,
   .txDMA_Stream = TELEMETRY_DMA_Stream_TX,
   .txDMA_Channel = TELEMETRY_DMA_Channel_TX,
+#if defined(TELEMETRY_DMA_Stream_RX)
+  .rxDMA = TELEMETRY_DMA,
+  .rxDMA_Stream = TELEMETRY_DMA_Stream_RX,
+  .rxDMA_Channel = TELEMETRY_DMA_Channel_RX,
+#else
   .rxDMA = nullptr,
   .rxDMA_Stream = 0,
   .rxDMA_Channel = 0,
+#endif
 #if defined(STM32H7) || (STM32H7RS)
   .set_input = nullptr,
 #else
diff --git a/radio/src/targets/common/arm/stm32/stm32_serial_driver.cpp b/radio/src/targets/common/arm/stm32/stm32_serial_driver.cpp
index 99050e8a6..d38575340 100644
--- a/radio/src/targets/common/arm/stm32/stm32_serial_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/stm32_serial_driver.cpp
@@ -337,7 +337,22 @@ static void stm32_serial_send_byte(void* ctx, uint8_t c)
   }
 }
 
-#define IS_CCM_RAM(addr) (((uint32_t)(addr) & (uint32_t)0xFFF00000) == 0x10000000)
+#if defined(STM32F4)
+extern uint32_t _sram;
+extern uint32_t _eram;
+#define _IS_DMA_BUFFER(addr) \
+  ((intptr_t)(addr) >= (intptr_t)&_sram && (intptr_t)(addr) <= (intptr_t)&_eram)
+#elif defined(STM32H7) || defined(STM32H7RS)
+extern uint32_t _s_dram;
+extern uint32_t _e_dram;
+#define _IS_DMA_BUFFER(addr)                 \
+  ((intptr_t)(addr) >= (intptr_t)&_s_dram && \
+   (intptr_t)(addr) <= (intptr_t)&_e_dram)
+#else
+#define _IS_DMA_BUFFER(addr) (true)
+#endif
+
+#define _IS_ALIGNED(addr) (((intptr_t)(addr) & 3U) == 0U)
 
 static void stm32_serial_send_buffer(void* ctx, const uint8_t* data, uint32_t size)
 {
@@ -347,10 +362,7 @@ static void stm32_serial_send_buffer(void* ctx, const uint8_t* data, uint32_t si
   // try TX DMA first
   auto sp = st->sp;
   auto usart = sp->usart;
-  if (usart->txDMA && !IS_CCM_RAM(data)) {
-#if defined(STM32H7) || defined(STM32H7RS)
-    SCB_CleanDCache_by_Addr((void*)data, size);
-#endif
+  if (usart->txDMA && _IS_DMA_BUFFER(data) && _IS_ALIGNED(data)) {
     stm32_usart_send_buffer(usart, data, size);
     return;
   }
diff --git a/radio/src/targets/common/arm/stm32/stm32_usart_driver.cpp b/radio/src/targets/common/arm/stm32/stm32_usart_driver.cpp
index f5e287168..cae16721f 100644
--- a/radio/src/targets/common/arm/stm32/stm32_usart_driver.cpp
+++ b/radio/src/targets/common/arm/stm32/stm32_usart_driver.cpp
@@ -28,6 +28,12 @@
 
 #include <string.h>
 
+#if defined(STM32H7) || defined(STM32H7RS)
+  #define IS_HALF_DUPLEX(usart) ((usart)->set_input || (usart)->rxGPIO == GPIO_UNDEF)
+#else
+  #define IS_HALF_DUPLEX(usart) ((usart)->set_input)
+#endif
+
 // WARNING:
 //
 // NVIC_GetEnableIRQ is stolen from "${THIRDPARTY_DIR}/CMSIS/Include/core_cm4.h".
@@ -66,19 +72,19 @@ static void _enable_tx_dma_irq(const stm32_usart_t* usart)
 
 static inline void _half_duplex_input(const stm32_usart_t* usart)
 {
-  if (usart->set_input) {
-    usart->set_input(true);
+  if (usart->set_input) usart->set_input(true);
+
+  if (IS_HALF_DUPLEX(usart)) {
     LL_USART_EnableDirectionRx(usart->USARTx);
-    LL_USART_DisableDirectionTx(usart->USARTx);
   }
 }
 
 static inline void _half_duplex_output(const stm32_usart_t* usart)
 {
-  if (usart->set_input) {
-    usart->set_input(false);
+  if (usart->set_input) usart->set_input(false);
+
+  if (IS_HALF_DUPLEX(usart)) {
     LL_USART_DisableDirectionRx(usart->USARTx);
-    LL_USART_EnableDirectionTx(usart->USARTx);
   }
 }
 
@@ -370,27 +376,25 @@ void stm32_usart_deinit_rx_dma(const stm32_usart_t* usart)
 void stm32_usart_rx_inversion(const stm32_usart_t* usart, bool on)
 {
   bool enableUart = false;
-  if(LL_USART_IsEnabled(usart->USARTx))
-  {
+  if (LL_USART_IsEnabled(usart->USARTx)) {
     LL_USART_Disable(usart->USARTx);
     enableUart = true;
   }
-  LL_USART_SetRXPinLevel(usart->USARTx, on?LL_USART_RXPIN_LEVEL_INVERTED:LL_USART_RXPIN_LEVEL_STANDARD);
-  if(enableUart)
-    LL_USART_Enable(usart->USARTx);
+  LL_USART_SetRXPinLevel(usart->USARTx, on ? LL_USART_RXPIN_LEVEL_INVERTED
+                                           : LL_USART_RXPIN_LEVEL_STANDARD);
+  if (enableUart) LL_USART_Enable(usart->USARTx);
 }
 
 void stm32_usart_tx_inversion(const stm32_usart_t* usart, bool on)
 {
   bool enableUart = false;
-  if(LL_USART_IsEnabled(usart->USARTx))
-  {
+  if (LL_USART_IsEnabled(usart->USARTx)) {
     LL_USART_Disable(usart->USARTx);
     enableUart = true;
   }
-  LL_USART_SetTXPinLevel(usart->USARTx, on?LL_USART_TXPIN_LEVEL_INVERTED:LL_USART_TXPIN_LEVEL_STANDARD);
-  if(enableUart)
-    LL_USART_Enable(usart->USARTx);
+  LL_USART_SetTXPinLevel(usart->USARTx, on ? LL_USART_TXPIN_LEVEL_INVERTED
+                                           : LL_USART_TXPIN_LEVEL_STANDARD);
+  if (enableUart) LL_USART_Enable(usart->USARTx);
 }
 #endif
 
@@ -424,6 +428,24 @@ bool stm32_usart_init(const stm32_usart_t* usart, const etx_serial_init* params)
     gpio_init_af(usart->txGPIO, af, _get_pin_speed(params->baudrate));
   }
   
+  bool half_duplex = usart->set_input;
+
+#if defined(STM32H7) || defined(STM32H7RS)
+  bool one_wire_half_duplex =
+      usart->rxGPIO == GPIO_UNDEF && (params->direction & ETX_Dir_RX);
+
+  if (one_wire_half_duplex) {
+    if (params->direction & ETX_Dir_TX) {
+      LL_GPIO_SetPinPull(
+          gpio_get_port(usart->txGPIO), 1 << gpio_get_pin(usart->txGPIO),
+          params->polarity ? LL_GPIO_PULL_UP : LL_GPIO_PULL_DOWN);
+    }
+    LL_USART_ConfigHalfDuplexMode(usart->USARTx);
+  }
+
+  half_duplex = half_duplex || one_wire_half_duplex;
+#endif
+
   LL_USART_InitTypeDef usartInit;
   LL_USART_StructInit(&usartInit);
 
@@ -459,22 +481,15 @@ bool stm32_usart_init(const stm32_usart_t* usart, const etx_serial_init* params)
     usartInit.TransferDirection |= LL_USART_DIRECTION_TX;
 
   LL_USART_Init(usart->USARTx, &usartInit);
-#if defined(STM32H7) || defined (STM32H7RS)
-  if(usart->rxGPIO == GPIO_UNDEF)
-  {
-    LL_USART_EnableHalfDuplex(usart->USARTx);
-  }
-#endif
   LL_USART_Enable(usart->USARTx);
 
-
   if (params->direction & ETX_Dir_TX) {
     // Enable TX DMA request
     if (usart->txDMA) {
       LL_USART_EnableDMAReq_TX(usart->USARTx);
 
       // 2-wire half-duplex: setup TX DMA IRQ
-      if (usart->set_input && (int32_t)(usart->txDMA_IRQn) >= 0) {
+      if (half_duplex && (int32_t)(usart->txDMA_IRQn) >= 0) {
         _enable_tx_dma_irq(usart);
       }
     }
@@ -487,8 +502,9 @@ bool stm32_usart_init(const stm32_usart_t* usart, const etx_serial_init* params)
     }
 
     // half-duplex: start in input mode
-    if (usart->set_input)
+    if (half_duplex) {
       _half_duplex_input(usart);
+    }
   }
 
   if (((params->direction & ETX_Dir_TX) && !usart->txDMA) ||
@@ -528,7 +544,7 @@ void stm32_usart_send_byte(const stm32_usart_t* usart, uint8_t byte)
   // TODO: split into 2 steps to avoid blocking on send
   while (!LL_USART_IsActiveFlag_TXE(usart->USARTx));
 
-  if (usart->set_input) {
+  if (IS_HALF_DUPLEX(usart)) {
     _half_duplex_output(usart);
 
     // switch back to input after TC
@@ -573,8 +589,9 @@ void stm32_usart_send_buffer(const stm32_usart_t* usart, const uint8_t * data, u
 
     LL_DMA_Init(usart->txDMA, usart->txDMA_Stream, &dmaInit);
 
-    if (usart->set_input && (int32_t)(usart->txDMA_IRQn) >= 0) {
+    if (IS_HALF_DUPLEX(usart) && (int32_t)(usart->txDMA_IRQn) >= 0) {
       LL_DMA_EnableIT_TC(usart->txDMA, usart->txDMA_Stream);
+      LL_USART_ClearFlag_TC(usart->USARTx);
     }
     LL_DMA_EnableStream(usart->txDMA, usart->txDMA_Stream);
 #endif // !STM32H7RS
@@ -779,13 +796,5 @@ void stm32_usart_tx_dma_isr(const stm32_usart_t* usart)
     return;
 
   auto USARTx = usart->USARTx;
-
-  // clear TC flag before enabling USART TC interrupt:
-  //  -> TC flag will be re-triggered once the last byte which has
-  //     just been transfered from DMA to USART will be transmitted,
-  //     thus triggering TELEMETRY_USART_IRQHandler(), which will
-  //     switch from output to input mode.
-  //
-  LL_USART_ClearFlag_TC(USARTx);
   LL_USART_EnableIT_TC(USARTx);
 }