diff --git a/armsrc/appmain.c b/armsrc/appmain.c
index 7c58fd7e6..15d939a35 100644
--- a/armsrc/appmain.c
+++ b/armsrc/appmain.c
@@ -208,12 +208,11 @@ void MeasureAntennaTuning(void) {
     FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_READER_RX_XCORR);
     SpinDelay(50);
 
+#if defined RDV4
+    payload.v_hf = (MAX_ADC_HF_VOLTAGE_RDV40 * AvgAdc(ADC_CHAN_HF_RDV40)) >> 10;
+#else
     payload.v_hf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
-
-    // RDV40 will hit the roof, try other ADC channel used in that hardware revision.
-    if (payload.v_hf > MAX_ADC_HF_VOLTAGE - 300) {
-        payload.v_hf = (MAX_ADC_HF_VOLTAGE_RDV40 * AvgAdc(ADC_CHAN_HF_RDV40)) >> 10;
-    }
+#endif
 
     FpgaWriteConfWord(FPGA_MAJOR_MODE_OFF);
     reply_ng(CMD_MEASURE_ANTENNA_TUNING, PM3_SUCCESS, (uint8_t *)&payload, sizeof(payload));
@@ -222,16 +221,13 @@ void MeasureAntennaTuning(void) {
 
 // Measure HF in milliVolt
 uint16_t MeasureAntennaTuningHfData(void) {
-    uint16_t volt = 0;
-    uint16_t avg = AvgAdc(ADC_CHAN_HF);
-    volt = (MAX_ADC_HF_VOLTAGE * avg) >> 10;
-    bool use_high = (volt > MAX_ADC_HF_VOLTAGE - 300);
 
-    if (use_high) {
-        volt = (MAX_ADC_HF_VOLTAGE_RDV40 * AvgAdc(ADC_CHAN_HF_RDV40)) >> 10;
-//        volt = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
-    }
-    return volt;
+#if defined RDV4
+    return (MAX_ADC_HF_VOLTAGE_RDV40 * AvgAdc(ADC_CHAN_HF_RDV40)) >> 10;
+#else
+    return (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
+#endif
+
 }
 
 // Measure LF in milliVolt
@@ -532,7 +528,6 @@ void ListenReaderField(uint8_t limit) {
     uint16_t lf_av = 0, lf_av_new, lf_baseline = 0, lf_max = 0;
     uint16_t hf_av = 0, hf_av_new,  hf_baseline = 0, hf_max = 0;
     uint16_t mode = 1, display_val, display_max;
-    bool use_high = false;
 
     // switch off FPGA - we don't want to measure our own signal
     // 20180315 - iceman,  why load this before and then turn off?
@@ -549,15 +544,12 @@ void ListenReaderField(uint8_t limit) {
 
     if (limit == HF_ONLY) {
 
-        hf_av = hf_max = AvgAdc(ADC_CHAN_HF);
-
+#if defined RDV4
         // iceman,  useless,  since we are measuring readerfield,  not our field.  My tests shows a max of 20v from a reader.
-        // RDV40 will hit the roof, try other ADC channel used in that hardware revision.
-        use_high = (((MAX_ADC_HF_VOLTAGE * hf_max) >> 10) > MAX_ADC_HF_VOLTAGE - 300);
-        if (use_high) {
-            hf_av = hf_max = AvgAdc(ADC_CHAN_HF_RDV40);
-        }
-
+        hf_av = hf_max = AvgAdc(ADC_CHAN_HF_RDV40);
+#else
+        hf_av = hf_max = AvgAdc(ADC_CHAN_HF);    
+#endif
         Dbprintf("HF 13.56MHz Baseline: %dmV", (MAX_ADC_HF_VOLTAGE * hf_av) >> 10);
         hf_baseline = hf_av;
     }
@@ -608,8 +600,11 @@ void ListenReaderField(uint8_t limit) {
                     LED_B_OFF();
             }
 
-            hf_av_new = (use_high) ? AvgAdc(ADC_CHAN_HF_RDV40) :  AvgAdc(ADC_CHAN_HF);
-
+#if defined RDV4
+            hf_av_new = AvgAdc(ADC_CHAN_HF_RDV40);
+#else
+            hf_av_new = AvgAdc(ADC_CHAN_HF);
+#endif
             // see if there's a significant change
             if (ABS(hf_av - hf_av_new) > REPORT_CHANGE) {
                 Dbprintf("HF 13.56MHz Field Change: %5dmV", (MAX_ADC_HF_VOLTAGE * hf_av_new) >> 10);
diff --git a/armsrc/iso14443a.c b/armsrc/iso14443a.c
index b68edf58a..abfe07f10 100644
--- a/armsrc/iso14443a.c
+++ b/armsrc/iso14443a.c
@@ -1787,7 +1787,13 @@ int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *par) {
         ADC_MODE_PRESCALE(63) |
         ADC_MODE_STARTUP_TIME(1) |
         ADC_MODE_SAMPLE_HOLD_TIME(15);
+
+#if defined RDV4
+    AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF_RDV40);
+#else
     AT91C_BASE_ADC->ADC_CHER = ADC_CHANNEL(ADC_CHAN_HF);
+#endif
+
     // start ADC
     AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
 
@@ -1811,12 +1817,19 @@ int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *par) {
         ++check;
 
         // test if the field exists
-        if (AT91C_BASE_ADC->ADC_SR & ADC_END_OF_CONVERSION(ADC_CHAN_HF)) {
+#if defined RDV4        
+        if (AT91C_BASE_ADC->ADC_SR & ADC_END_OF_CONVERSION(ADC_CHAN_HF_RDV40)) {
+            
             analogCnt++;
-            analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF];
+            
+            analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF_RDV40];
+            
             AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
+            
             if (analogCnt >= 32) {
+
                 if ((MAX_ADC_HF_VOLTAGE_RDV40 * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
+
                     if (timer == 0) {
                         timer = GetTickCount();
                     } else {
@@ -1832,6 +1845,35 @@ int EmGetCmd(uint8_t *received, uint16_t *len, uint8_t *par) {
                 analogAVG = 0;
             }
         }
+#else
+        if (AT91C_BASE_ADC->ADC_SR & ADC_END_OF_CONVERSION(ADC_CHAN_HF)) {
+            
+            analogCnt++;
+            
+            analogAVG += AT91C_BASE_ADC->ADC_CDR[ADC_CHAN_HF];
+            
+            AT91C_BASE_ADC->ADC_CR = AT91C_ADC_START;
+            
+            if (analogCnt >= 32) {
+
+                if ((MAX_ADC_HF_VOLTAGE * (analogAVG / analogCnt) >> 10) < MF_MINFIELDV) {
+
+                    if (timer == 0) {
+                        timer = GetTickCount();
+                    } else {
+                        // 50ms no field --> card to idle state
+                        if (GetTickCountDelta(timer) > 50) {
+                            return 2;
+                        }
+                    }
+                } else {
+                    timer = 0;
+                }
+                analogCnt = 0;
+                analogAVG = 0;
+            }
+        }
+#endif
 
         // receive and test the miller decoding
         if (AT91C_BASE_SSC->SSC_SR & (AT91C_SSC_RXRDY)) {
diff --git a/armsrc/iso14443b.c b/armsrc/iso14443b.c
index d68ddd044..31f2cae58 100644
--- a/armsrc/iso14443b.c
+++ b/armsrc/iso14443b.c
@@ -635,7 +635,12 @@ void SimulateIso14443bTag(uint32_t pupi) {
 
         // find reader field
         if (cardSTATE == SIM_NOFIELD) {
+
+#if defined RDV4
+            vHf = (MAX_ADC_HF_VOLTAGE_RDV40 * AvgAdc(ADC_CHAN_HF_RDV40)) >> 10;
+#else
             vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
+#endif
             if (vHf > MF_MINFIELDV) {
                 cardSTATE = SIM_IDLE;
                 LED_A_ON();
diff --git a/armsrc/mifaresim.c b/armsrc/mifaresim.c
index 80881c416..0dcbe404a 100644
--- a/armsrc/mifaresim.c
+++ b/armsrc/mifaresim.c
@@ -537,7 +537,13 @@ void Mifare1ksim(uint16_t flags, uint8_t exitAfterNReads, uint8_t *datain, uint1
 
         // find reader field
         if (cardSTATE == MFEMUL_NOFIELD) {
-            vHf = (MAX_ADC_HF_VOLTAGE_RDV40 * AvgAdc(ADC_CHAN_HF)) >> 10;
+            
+#if defined RDV4
+            vHf = (MAX_ADC_HF_VOLTAGE_RDV40 * AvgAdc(ADC_CHAN_HF_RDV40)) >> 10;
+#else
+            vHf = (MAX_ADC_HF_VOLTAGE * AvgAdc(ADC_CHAN_HF)) >> 10;
+#endif
+          
             if (vHf > MF_MINFIELDV) {
                 cardSTATE_TO_IDLE();
                 LED_A_ON();
diff --git a/armsrc/thinfilm.c b/armsrc/thinfilm.c
index 46fa5a920..e4b2e9b23 100644
--- a/armsrc/thinfilm.c
+++ b/armsrc/thinfilm.c
@@ -52,10 +52,11 @@ void ReadThinFilm(void) {
 uint16_t FpgaSendQueueDelay;
 
 uint16_t ReadReaderField(void) {
-    uint16_t hf_av = AvgAdc(ADC_CHAN_HF);
-    if (((MAX_ADC_HF_VOLTAGE * hf_av) >> 10) > MAX_ADC_HF_VOLTAGE - 300)
-        hf_av = AvgAdc(ADC_CHAN_HF_RDV40);
-    return hf_av;
+#if defined RDV4
+    return AvgAdc(ADC_CHAN_HF_RDV40);
+#else
+    return AvgAdc(ADC_CHAN_HF);
+#endif
 }
 
 static void CodeThinfilmAsTag(const uint8_t *cmd, uint16_t len) {
@@ -119,13 +120,16 @@ void SimulateThinFilm(uint8_t *data, size_t len) {
     CodeThinfilmAsTag(data, len);
 
     FpgaDownloadAndGo(FPGA_BITSTREAM_HF);
+
     // Set up the synchronous serial port
     FpgaSetupSsc();
+
     // connect Demodulated Signal to ADC:
     SetAdcMuxFor(GPIO_MUXSEL_HIPKD);
 
     FpgaWriteConfWord(FPGA_MAJOR_MODE_HF_ISO14443A | FPGA_HF_ISO14443A_TAGSIM_MOD);
     SpinDelay(100);
+
     uint16_t hf_baseline = ReadReaderField();
 
     // Start the timer
diff --git a/common_arm/Makefile.hal b/common_arm/Makefile.hal
index 8fe070582..455672e5f 100644
--- a/common_arm/Makefile.hal
+++ b/common_arm/Makefile.hal
@@ -56,7 +56,7 @@ endef
 PLTNAME = Unknown Platform
 
 ifeq ($(PLATFORM),PM3RDV4)
-    PLATFORM_DEFS = -DWITH_SMARTCARD -DWITH_FLASH
+    PLATFORM_DEFS = -DWITH_SMARTCARD -DWITH_FLASH -DRDV4
     PLTNAME = Proxmark3 rdv4
 else ifeq ($(PLATFORM),PM3OTHER)
     PLTNAME = Proxmark3 Generic target