diff --git a/M17Control.cpp b/M17Control.cpp
index a5d5b34..fa9a9c6 100644
--- a/M17Control.cpp
+++ b/M17Control.cpp
@@ -257,7 +257,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 #endif
 		CM17Convolution conv;
 		unsigned char frame[M17_FN_LENGTH_BYTES + M17_PAYLOAD_LENGTH_BYTES];
-		conv.decodeData(data + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES, frame);
+		unsigned int convBER = conv.decodeData(data + 2U + M17_SYNC_LENGTH_BYTES + M17_LICH_FRAGMENT_FEC_LENGTH_BYTES, frame);
 
 		unsigned int fn = ((frame[0U] << 8) + (frame[1U] << 0)) & 0x7FU;
 
@@ -296,7 +296,7 @@ bool CM17Control::writeModem(unsigned char* data, unsigned int len)
 			errors += CUtils::countBits(rfData[offset] ^ data[offset]);
 		}
 
-		LogDebug("M17, FN: %u, errs: %u/144 (%.1f%%)", fn & 0x7FU, errors, float(errors) / 1.44F);
+		LogDebug("M17, FN: %u, errs: %u/%u/144 (%.1f%%)", fn & 0x7FU, errors, convBER, float(errors) / 1.44F);
 
 		m_rfBits += M17_FN_LENGTH_BITS + M17_PAYLOAD_LENGTH_BITS;
 		m_rfErrs += errors;
diff --git a/M17Convolution.cpp b/M17Convolution.cpp
index ae99c46..8ce22b8 100644
--- a/M17Convolution.cpp
+++ b/M17Convolution.cpp
@@ -118,7 +118,7 @@ void CM17Convolution::encodeData(const unsigned char* in, unsigned char* out) co
 	}
 }
 
-void CM17Convolution::decodeLinkSetup(const unsigned char* in, unsigned char* out)
+unsigned int CM17Convolution::decodeLinkSetup(const unsigned char* in, unsigned char* out)
 {
 	assert(in != NULL);
 	assert(out != NULL);
@@ -150,10 +150,10 @@ void CM17Convolution::decodeLinkSetup(const unsigned char* in, unsigned char* ou
 		decode(s0, s1);
 	}
 
-	chainback(out, 240U);
+	return chainback(out, 240U);
 }
 
-void CM17Convolution::decodeData(const unsigned char* in, unsigned char* out)
+unsigned int CM17Convolution::decodeData(const unsigned char* in, unsigned char* out)
 {
 	assert(in != NULL);
 	assert(out != NULL);
@@ -185,7 +185,7 @@ void CM17Convolution::decodeData(const unsigned char* in, unsigned char* out)
 		decode(s0, s1);
 	}
 
-	chainback(out, 160U);
+	return chainback(out, 160U);
 }
 
 void CM17Convolution::start()
@@ -229,7 +229,7 @@ void CM17Convolution::decode(uint8_t s0, uint8_t s1)
   m_newMetrics = tmp;
 }
 
-void CM17Convolution::chainback(unsigned char* out, unsigned int nBits)
+unsigned int CM17Convolution::chainback(unsigned char* out, unsigned int nBits)
 {
 	assert(out != NULL);
 
@@ -244,6 +244,15 @@ void CM17Convolution::chainback(unsigned char* out, unsigned int nBits)
 
 		WRITE_BIT1(out, nBits, bit != 0U);
 	}
+
+	unsigned int minCost = m_oldMetrics[0];
+
+	for (unsigned int i = 0U; i < NUM_OF_STATES; i++) {
+		if (m_oldMetrics[i] < minCost)
+			minCost = m_oldMetrics[i];
+	}
+
+	return minCost / (M >> 1);
 }
 
 void CM17Convolution::encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const
diff --git a/M17Convolution.h b/M17Convolution.h
index 91843ba..0c5c7c3 100644
--- a/M17Convolution.h
+++ b/M17Convolution.h
@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2020 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2020,2021 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -26,8 +26,8 @@ public:
 	CM17Convolution();
 	~CM17Convolution();
 
-	void decodeLinkSetup(const unsigned char* in, unsigned char* out);
-	void decodeData(const unsigned char* in, unsigned char* out);
+	unsigned int decodeLinkSetup(const unsigned char* in, unsigned char* out);
+	unsigned int decodeData(const unsigned char* in, unsigned char* out);
 
 	void encodeLinkSetup(const unsigned char* in, unsigned char* out) const;
 	void encodeData(const unsigned char* in, unsigned char* out) const;
@@ -42,7 +42,8 @@ private:
 
 	void start();
 	void decode(uint8_t s0, uint8_t s1);
-	void chainback(unsigned char* out, unsigned int nBits);
+
+	unsigned int chainback(unsigned char* out, unsigned int nBits);
 
 	void encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const;
 };
diff --git a/NXDNConvolution.cpp b/NXDNConvolution.cpp
index 10c4504..875752e 100644
--- a/NXDNConvolution.cpp
+++ b/NXDNConvolution.cpp
@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2009-2016,2018 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2009-2016,2018,2021 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -97,7 +97,7 @@ void CNXDNConvolution::decode(uint8_t s0, uint8_t s1)
   m_newMetrics = tmp;
 }
 
-void CNXDNConvolution::chainback(unsigned char* out, unsigned int nBits)
+unsigned int CNXDNConvolution::chainback(unsigned char* out, unsigned int nBits)
 {
 	assert(out != NULL);
 
@@ -112,6 +112,15 @@ void CNXDNConvolution::chainback(unsigned char* out, unsigned int nBits)
 
 		WRITE_BIT1(out, nBits, bit != 0U);
 	}
+
+	unsigned int minCost = m_oldMetrics[0];
+
+	for (unsigned int i = 0U; i < NUM_OF_STATES; i++) {
+		if (m_oldMetrics[i] < minCost)
+			minCost = m_oldMetrics[i];
+	}
+
+	return minCost / (M >> 1);
 }
 
 void CNXDNConvolution::encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const
diff --git a/NXDNConvolution.h b/NXDNConvolution.h
index d6171c9..805bc25 100644
--- a/NXDNConvolution.h
+++ b/NXDNConvolution.h
@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2015,2016,2018 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2015,2016,2018,2021 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -28,7 +28,8 @@ public:
 
 	void start();
 	void decode(uint8_t s0, uint8_t s1);
-	void chainback(unsigned char* out, unsigned int nBits);
+
+	unsigned int chainback(unsigned char* out, unsigned int nBits);
 
 	void encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const;
 
diff --git a/Version.h b/Version.h
index 888ab6a..afa0ef1 100644
--- a/Version.h
+++ b/Version.h
@@ -19,6 +19,6 @@
 #if !defined(VERSION_H)
 #define	VERSION_H
 
-const char* VERSION = "20210625";
+const char* VERSION = "20210627";
 
 #endif
diff --git a/YSFConvolution.cpp b/YSFConvolution.cpp
index e1d705a..c79bf2a 100644
--- a/YSFConvolution.cpp
+++ b/YSFConvolution.cpp
@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2009-2016 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2009-2016,2021 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -96,7 +96,7 @@ void CYSFConvolution::decode(uint8_t s0, uint8_t s1)
   m_newMetrics = tmp;
 }
 
-void CYSFConvolution::chainback(unsigned char* out, unsigned int nBits)
+unsigned int CYSFConvolution::chainback(unsigned char* out, unsigned int nBits)
 {
 	assert(out != NULL);
 
@@ -111,6 +111,15 @@ void CYSFConvolution::chainback(unsigned char* out, unsigned int nBits)
 
 		WRITE_BIT1(out, nBits, bit != 0U);
 	}
+
+	unsigned int minCost = m_oldMetrics[0];
+
+	for (unsigned int i = 0U; i < NUM_OF_STATES; i++) {
+		if (m_oldMetrics[i] < minCost)
+			minCost = m_oldMetrics[i];
+	}
+
+	return minCost / (M >> 1);
 }
 
 void CYSFConvolution::encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const
diff --git a/YSFConvolution.h b/YSFConvolution.h
index 23127e9..b49ddc5 100644
--- a/YSFConvolution.h
+++ b/YSFConvolution.h
@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2015,2016 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2015,2016.2021 by Jonathan Naylor G4KLX
  *
  *   This program is free software; you can redistribute it and/or modify
  *   it under the terms of the GNU General Public License as published by
@@ -28,7 +28,8 @@ public:
 
 	void start();
 	void decode(uint8_t s0, uint8_t s1);
-	void chainback(unsigned char* out, unsigned int nBits);
+
+	unsigned int chainback(unsigned char* out, unsigned int nBits);
 
 	void encode(const unsigned char* in, unsigned char* out, unsigned int nBits) const;