From c1171bc052129a641b04d3b8f4dd0a8b4ec25b20 Mon Sep 17 00:00:00 2001
From: Jonathan Naylor <naylorjs@yahoo.com>
Date: Tue, 13 Oct 2020 10:07:31 +0100
Subject: [PATCH 1/2] Regenerate the FICH correctly.

---
 Version.h      |  2 +-
 YSFControl.cpp | 25 +++++++++++++++++++++++--
 YSFFICH.cpp    | 14 +++++++++++++-
 YSFFICH.h      |  4 +++-
 4 files changed, 40 insertions(+), 5 deletions(-)

diff --git a/Version.h b/Version.h
index 28b79b8..d8d0145 100644
--- a/Version.h
+++ b/Version.h
@@ -19,6 +19,6 @@
 #if !defined(VERSION_H)
 #define	VERSION_H
 
-const char* VERSION = "20200924";
+const char* VERSION = "20201013";
 
 #endif
diff --git a/YSFControl.cpp b/YSFControl.cpp
index ac16e55..3830ff5 100644
--- a/YSFControl.cpp
+++ b/YSFControl.cpp
@@ -155,9 +155,30 @@ bool CYSFControl::writeModem(unsigned char *data, unsigned int len)
 
 	CYSFFICH fich;
 	bool valid = fich.decode(data + 2U);
+	if (!valid) {
+		unsigned char fi = m_lastFICH.getFI();
+		unsigned char ft = m_lastFICH.getFT();
+		unsigned char fn = m_lastFICH.getFN();
+		unsigned char bt = m_lastFICH.getBT();
+		unsigned char bn = m_lastFICH.getBN();
 
-	if (valid)
-		m_lastFICH = fich;
+		if (fi == YSF_FI_COMMUNICATIONS && ft > 0U) {
+			fn++;
+			if (fn > ft) {
+				fn = 0U;
+				if (bt > 0U)
+					bn++;
+			}
+		}
+
+		fich.setFI(YSF_FI_COMMUNICATIONS);
+		fich.setFN(fn);
+		fich.setFT(ft);
+		fich.setBN(bn);
+		fich.setBT(bt);
+	}
+
+	m_lastFICH = fich;
 
 #ifdef notdef
 	// Stop repeater packets coming through, unless we're acting as a remote gateway
diff --git a/YSFFICH.cpp b/YSFFICH.cpp
index 967b339..c1824fc 100644
--- a/YSFFICH.cpp
+++ b/YSFFICH.cpp
@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2016,2017,2019 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2016,2017,2019,2020 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
@@ -225,6 +225,18 @@ void CYSFFICH::setFI(unsigned char fi)
 	m_fich[0U] |= (fi << 6) & 0xC0U;
 }
 
+void CYSFFICH::setBN(unsigned char bn)
+{
+	m_fich[0U] &= 0xFCU;
+	m_fich[0U] |= bn & 0x03U;
+}
+
+void CYSFFICH::setBT(unsigned char bt)
+{
+	m_fich[1U] &= 0x3FU;
+	m_fich[1U] |= (bt << 6) & 0xC0U;
+}
+
 void CYSFFICH::setFN(unsigned char fn)
 {
 	m_fich[1U] &= 0xC7U;
diff --git a/YSFFICH.h b/YSFFICH.h
index b7d623c..5d27ac0 100644
--- a/YSFFICH.h
+++ b/YSFFICH.h
@@ -1,5 +1,5 @@
 /*
- *   Copyright (C) 2016,2017,2019 by Jonathan Naylor G4KLX
+ *   Copyright (C) 2016,2017,2019,2020 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
@@ -41,6 +41,8 @@ public:
 	unsigned char getDGId() const;
 
 	void setFI(unsigned char fi);
+	void setBN(unsigned char bn);
+	void setBT(unsigned char bt);
 	void setFN(unsigned char fn);
 	void setFT(unsigned char ft);
 	void setMR(unsigned char mr);

From ff19408e2d9144149500f322ee73179a62d4e0c8 Mon Sep 17 00:00:00 2001
From: Jonathan Naylor <naylorjs@yahoo.com>
Date: Tue, 13 Oct 2020 10:11:13 +0100
Subject: [PATCH 2/2] Fix bug added in FICH regeneration.

---
 YSFControl.cpp | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/YSFControl.cpp b/YSFControl.cpp
index 3830ff5..63d23ca 100644
--- a/YSFControl.cpp
+++ b/YSFControl.cpp
@@ -171,15 +171,13 @@ bool CYSFControl::writeModem(unsigned char *data, unsigned int len)
 			}
 		}
 
-		fich.setFI(YSF_FI_COMMUNICATIONS);
-		fich.setFN(fn);
-		fich.setFT(ft);
-		fich.setBN(bn);
-		fich.setBT(bt);
+		m_lastFICH.setFI(YSF_FI_COMMUNICATIONS);
+		m_lastFICH.setFN(fn);
+		m_lastFICH.setBN(bn);
+	} else {
+		m_lastFICH = fich;
 	}
 
-	m_lastFICH = fich;
-
 #ifdef notdef
 	// Stop repeater packets coming through, unless we're acting as a remote gateway
 	if (m_remoteGateway) {