From dbc30e97b4f98239492565e8b0b09ad7dfc8ec5a Mon Sep 17 00:00:00 2001
From: Bryan Biedenkapp <gatekeep@gmail.com>
Date: Sat, 10 Oct 2026 14:50:31 -0400
Subject: [PATCH] correct DMR ACK_RSP dstId truncation;

---
 src/common/dmr/lc/csbk/CSBK_ACK_RSP.cpp |  2 +-
 tests/dmr/Tier3Lifecycle_Tests.cpp      | 20 ++++++++++++++++++++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/src/common/dmr/lc/csbk/CSBK_ACK_RSP.cpp b/src/common/dmr/lc/csbk/CSBK_ACK_RSP.cpp
index faac3f75..ebec778e 100644
--- a/src/common/dmr/lc/csbk/CSBK_ACK_RSP.cpp
+++ b/src/common/dmr/lc/csbk/CSBK_ACK_RSP.cpp
@@ -45,7 +45,7 @@ bool CSBK_ACK_RSP::decode(const uint8_t* data)
 
     m_GI = (((csbkValue >> 56) & 0xFFU) & 0x40U) == 0x40U;                          // Group/Individual Flag
     m_reason = (uint8_t)((csbkValue >> 33) & 0xFFU);                                // Reason Code
-    m_dstId = (uint32_t)((csbkValue >> 24) & 0xFFFFU);                              // Target Radio Address
+    m_dstId = (uint32_t)((csbkValue >> 24) & 0xFFFFFFU);                            // Target Radio Address
     m_srcId = (uint32_t)(csbkValue & 0xFFFFFFU);                                    // Source Radio Address
 
     return true;
diff --git a/tests/dmr/Tier3Lifecycle_Tests.cpp b/tests/dmr/Tier3Lifecycle_Tests.cpp
index 98cf968b..b4eba24f 100644
--- a/tests/dmr/Tier3Lifecycle_Tests.cpp
+++ b/tests/dmr/Tier3Lifecycle_Tests.cpp
@@ -10,6 +10,7 @@
 
 #include "host/Defines.h"
 #include "common/dmr/DMRDefines.h"
+#include "common/dmr/lc/csbk/CSBK_ACK_RSP.h"
 #include "common/dmr/lc/csbk/CSBK_MAINT.h"
 #include "common/dmr/lc/csbk/CSBK_P_CLEAR.h"
 #include "common/lookups/ChannelLookup.h"
@@ -20,6 +21,25 @@
 using namespace dmr::defines;
 using namespace dmr::lc::csbk;
 
+TEST_CASE("DMR Tier III acknowledgement preserves 24-bit target addresses", "[dmr][tier3][csbk]")
+{
+    CSBK_ACK_RSP encoded;
+    encoded.setLastBlock(true);
+    encoded.setReason(ReasonCode::TS_ACK_RSN_MSG);
+    encoded.setResponse(0x55U);
+    encoded.setDstId(0xABCDEFU);
+    encoded.setSrcId(WUID_TSI);
+
+    uint8_t burst[DMR_FRAME_LENGTH_BYTES] = { 0U };
+    encoded.encode(burst);
+
+    CSBK_ACK_RSP decoded;
+    decoded.setDataType(DataType::CSBK);
+    REQUIRE(decoded.decode(burst));
+    CHECK(decoded.getDstId() == 0xABCDEFU);
+    CHECK(decoded.getSrcId() == WUID_TSI);
+}
+
 TEST_CASE("DMR Tier III maintenance preserves 24-bit addresses", "[dmr][tier3][csbk]")
 {
     CSBK_MAINT encoded;