diff --git a/config.yml b/config.yml
index 0a39839c..85838372 100644
--- a/config.yml
+++ b/config.yml
@@ -47,6 +47,7 @@ protocols:
         voiceOnControl: false
         inhibitIllegal: false
         legacyGroupGrnt: true
+        legacyGroupReg: false
         verifyAff: false
         verifyReg: false
         dumpDataPacket: false
diff --git a/network/RemoteControl.cpp b/network/RemoteControl.cpp
index 44463417..0a7fd1bc 100644
--- a/network/RemoteControl.cpp
+++ b/network/RemoteControl.cpp
@@ -83,6 +83,7 @@ using namespace modem;
 #define RCD_P25_PATCH_CMD           "p25-patch"
 
 #define RCD_P25_RELEASE_GRANTS      "p25-rel-grnts"
+#define RCD_P25_RELEASE_AFFS        "p25-rel-affs"
 
 const uint32_t RC_BUFFER_LENGTH = 100U;
 
@@ -572,6 +573,22 @@ void RemoteControl::process(Host* host, dmr::Control* dmr, p25::Control* p25)
                     LogError(LOG_RCON, CMD_FAILED_STR "P25 mode is not enabled!");
                 }
             }
+            else if (rcom == RCD_P25_RELEASE_AFFS) {
+                // Command is in the form of: "p25-rel-affs <group>"
+                if (p25 != NULL) {
+                    uint32_t grp = getArgUInt32(args, 0U);
+
+                    if (grp == 0) {
+                        p25->trunk()->clearGrpAff(0, true);
+                    }
+                    else {
+                        p25->trunk()->clearGrpAff(grp, false);
+                    }
+                }
+                else {
+                    LogError(LOG_RCON, CMD_FAILED_STR "P25 mode is not enabled!");
+                }
+            }
             else {
                 args.clear();
                 LogError(LOG_RCON, BAD_CMD_STR " (\"%s\")", rcom.c_str());
diff --git a/p25/Control.cpp b/p25/Control.cpp
index d795eddc..a9b95b28 100644
--- a/p25/Control.cpp
+++ b/p25/Control.cpp
@@ -89,6 +89,7 @@ Control::Control(uint32_t nac, uint32_t callHang, uint32_t queueSize, modem::Mod
     m_network(network),
     m_inhibitIllegal(false),
     m_legacyGroupGrnt(true),
+    m_legacyGroupReg(false),
     m_duplex(duplex),
     m_control(false),
     m_continuousControl(false),
@@ -112,6 +113,7 @@ Control::Control(uint32_t nac, uint32_t callHang, uint32_t queueSize, modem::Mod
     m_hangCount(3U * 8U),
     m_preambleCount(0U),
     m_ccFrameCnt(0U),
+    m_ccSeq(0U),
     m_nid(nac),
     m_rssiMapper(rssiMapper),
     m_rssi(0U),
@@ -181,6 +183,7 @@ void Control::setOptions(yaml::Node& conf, const std::string cwCallsign, const s
 
     m_inhibitIllegal = p25Protocol["inhibitIllegal"].as<bool>(false);
     m_legacyGroupGrnt = p25Protocol["legacyGroupGrnt"].as<bool>(true);
+    m_legacyGroupReg = p25Protocol["legacyGroupReg"].as<bool>(false);
 
     m_trunk->m_verifyAff = p25Protocol["verifyAff"].as<bool>(false);
     m_trunk->m_verifyReg = p25Protocol["verifyReg"].as<bool>(false);
@@ -226,6 +229,7 @@ void Control::setOptions(yaml::Node& conf, const std::string cwCallsign, const s
 
         LogInfo("    Inhibit Illegal: %s", m_inhibitIllegal ? "yes" : "no");
         LogInfo("    Legacy Group Grant: %s", m_legacyGroupGrnt ? "yes" : "no");
+        LogInfo("    Legacy Group Registration: %s", m_legacyGroupReg ? "yes" : "no");
         LogInfo("    Verify Affiliation: %s", m_trunk->m_verifyAff ? "yes" : "no");
         LogInfo("    Verify Registration: %s", m_trunk->m_verifyReg ? "yes" : "no");
 
@@ -455,13 +459,18 @@ bool Control::writeControlRF()
         return false;
     }
 
+    if (m_ccSeq == 5U) {
+        m_ccSeq = 0U;
+    }
+
     if (m_ccFrameCnt == 254U) {
         m_ccFrameCnt = 0U;
     }
 
     if (m_netState == RS_NET_IDLE && m_rfState == RS_RF_LISTENING) {
-        m_trunk->writeRF_ControlData(m_ccFrameCnt, true);
+        m_trunk->writeRF_ControlData(m_ccFrameCnt, m_ccSeq, true);
         m_ccFrameCnt++;
+        m_ccSeq++;
         return true;
     }
 
diff --git a/p25/Control.h b/p25/Control.h
index c4004185..137b5190 100644
--- a/p25/Control.h
+++ b/p25/Control.h
@@ -122,6 +122,7 @@ namespace p25
 
         bool m_inhibitIllegal;
         bool m_legacyGroupGrnt;
+        bool m_legacyGroupReg;
 
         bool m_duplex;
         bool m_control;
@@ -151,7 +152,9 @@ namespace p25
 
         uint32_t m_hangCount;
         uint32_t m_preambleCount;
+        
         uint8_t m_ccFrameCnt;
+        uint8_t m_ccSeq;
 
         NID m_nid;
 
diff --git a/p25/TrunkPacket.cpp b/p25/TrunkPacket.cpp
index 76aa35b5..e0758112 100644
--- a/p25/TrunkPacket.cpp
+++ b/p25/TrunkPacket.cpp
@@ -339,6 +339,8 @@ bool TrunkPacket::process(uint8_t* data, uint32_t len)
                     LogMessage(LOG_RF, P25_TSDU_STR ", TSBK_IOSP_GRP_VCH (Group Voice Channel Request), srcId = %u, dstId = %u", srcId, dstId);
                 }
 
+                ::ActivityLog("P25", true, "received group grant request from %u to TG %u", srcId, dstId);
+
                 writeRF_TSDU_Grant(true, false);
                 break;
             case TSBK_IOSP_UU_VCH:
@@ -358,6 +360,8 @@ bool TrunkPacket::process(uint8_t* data, uint32_t len)
                     LogMessage(LOG_RF, P25_TSDU_STR ", TSBK_IOSP_UU_VCH (Unit-to-Unit Voice Channel Request), srcId = %u, dstId = %u", srcId, dstId);
                 }
 
+                ::ActivityLog("P25", true, "received unit-to-unit grant request from %u to %u", srcId, dstId);
+
                 writeRF_TSDU_UU_Ans_Req(srcId, dstId);
                 break;
             case TSBK_IOSP_UU_ANS:
@@ -375,6 +379,8 @@ bool TrunkPacket::process(uint8_t* data, uint32_t len)
                         m_rfTSBK.getResponse(), srcId, dstId);
                 }
 
+                writeRF_TSDU_ACK_FNE(srcId, TSBK_IOSP_UU_ANS, true);
+
                 if (m_rfTSBK.getResponse() == P25_ANS_RSP_PROCEED) {
                     writeRF_TSDU_Grant(false, false);
                 }
@@ -397,6 +403,8 @@ bool TrunkPacket::process(uint8_t* data, uint32_t len)
                         m_rfTSBK.getResponse(), srcId);
                 }
 
+                writeRF_TSDU_ACK_FNE(srcId, TSBK_IOSP_TELE_INT_ANS, true);
+
                 if (m_rfTSBK.getResponse() == P25_ANS_RSP_PROCEED) {
                     //writeRF_TSDU_Grant(false);
                     writeRF_TSDU_Deny(P25_DENY_RSN_SYS_UNSUPPORTED_SVC, TSBK_IOSP_TELE_INT_ANS);
@@ -677,6 +685,19 @@ bool TrunkPacket::processNetwork(uint8_t* data, uint32_t len, lc::LC& control, d
                 resetStatusCommand(m_netTSBK);
 
                 switch (m_netTSBK.getLCO()) {
+                    case TSBK_IOSP_UU_ANS:
+                        if (m_netTSBK.getResponse() > 0U) {
+                            if (m_verbose) {
+                                LogMessage(LOG_NET, P25_TSDU_STR ", TSBK_IOSP_UU_ANS (Unit-to-Unit Answer Response), response = $%02X, srcId = %u, dstId = %u",
+                                    m_netTSBK.getResponse(), srcId, dstId);
+                            }
+                        }
+                        else {
+                            if (m_verbose) {
+                                LogMessage(LOG_NET, P25_TSDU_STR ", TSBK_IOSP_UU_ANS (Unit-to-Unit Answer Request), srcId = %u, dstId = %u", srcId, dstId);
+                            }
+                        }
+                        break;
                     case TSBK_IOSP_STS_UPDT:
                         // validate the source RID
                         VALID_SRCID_NET("TSBK_IOSP_STS_UPDT (Status Update)", srcId);
@@ -751,14 +772,14 @@ bool TrunkPacket::processNetwork(uint8_t* data, uint32_t len, lc::LC& control, d
                         break;
                     case TSBK_OSP_DENY_RSP:
                         if (m_verbose) {
-                            LogMessage(LOG_NET, P25_TSDU_STR ", TSBK_OSP_DENY_RSP (Deny Response), reason = %u, srcId = %u, dstId = %u", 
-                                m_netTSBK.getResponse(), m_netTSBK.getSrcId(), m_netTSBK.getDstId());
+                            LogMessage(LOG_NET, P25_TSDU_STR ", TSBK_OSP_DENY_RSP (Deny Response), AIV = %u, reason = $%02X, srcId = %u, dstId = %u",
+                                m_netTSBK.getAIV(), m_netTSBK.getResponse(), m_netTSBK.getSrcId(), m_netTSBK.getDstId());
                         }
                         break;
                     case TSBK_OSP_QUE_RSP:
                         if (m_verbose) {
-                            LogMessage(LOG_NET, P25_TSDU_STR ", TSBK_OSP_QUE_RSP (Queue Response), reason = %u, srcId = %u, dstId = %u", 
-                                m_netTSBK.getResponse(), m_netTSBK.getSrcId(), m_netTSBK.getDstId());
+                            LogMessage(LOG_NET, P25_TSDU_STR ", TSBK_OSP_QUE_RSP (Queue Response), AIV = %u, reason = $%02X, srcId = %u, dstId = %u",
+                                m_netTSBK.getAIV(), m_netTSBK.getResponse(), m_netTSBK.getSrcId(), m_netTSBK.getDstId());
                         }
                         break;
                     default:
@@ -959,6 +980,42 @@ void TrunkPacket::releaseDstIdGrant(uint32_t dstId, bool releaseAll)
     }
 }
 
+/// <summary>
+/// Helper to release group affiliations.
+/// </summary>
+/// <param name="dstId"></param>
+/// <param name="releaseAll"></param>
+void TrunkPacket::clearGrpAff(uint32_t dstId, bool releaseAll)
+{
+    if (dstId == 0U && !releaseAll) {
+        return;
+    }
+
+    std::vector<uint32_t> srcToRel = std::vector<uint32_t>();
+    if (dstId == 0U && releaseAll) {
+        LogWarning(LOG_RF, "P25, releasing all group affiliations");
+        for (auto it = m_grpAffTable.begin(); it != m_grpAffTable.end(); ++it) {
+            uint32_t srcId = it->first;
+            srcToRel.push_back(srcId);
+        }
+    }
+    else {
+        LogWarning(LOG_RF, "P25, releasing group affiliations, dstId = %u", dstId);
+        for (auto it = m_grpAffTable.begin(); it != m_grpAffTable.end(); ++it) {
+            uint32_t srcId = it->first;
+            uint32_t grpId = it->second;
+            if (grpId == dstId) {
+                srcToRel.push_back(srcId);
+            }
+        }
+    }
+
+    // release affiliations
+    for (auto it = srcToRel.begin(); it != srcToRel.end(); ++it) {
+        writeRF_TSDU_U_Dereg_Ack(*it);
+    }
+}
+
 /// <summary>
 ///
 /// </summary>
@@ -1258,124 +1315,91 @@ void TrunkPacket::writeNetworkRF(const uint8_t* data, bool autoReset)
 /// Helper to write control channel packet data.
 /// </summary>
 /// <param name="frameCnt"></param>
+/// <param name="n"></param>
 /// <param name="adjSS"></param>
-void TrunkPacket::writeRF_ControlData(uint8_t frameCnt, bool adjSS)
+void TrunkPacket::writeRF_ControlData(uint8_t frameCnt, uint8_t n, bool adjSS)
 {
+    uint8_t i = 0U, seqCnt = 0U;
+
     if (!m_p25->m_control) {
         return;
     }
 
-    m_rfTSBK.reset();
-
-    bool alt = (frameCnt % 2) > 0U;
-    if (m_debug) {
-        LogDebug(LOG_P25, "writeRF_ControlData, mbfCnt = %u, frameCnt = %u, alt = %u, adjSS = %u", m_mbfCnt, frameCnt, alt, adjSS);
-    }
-
-    queueRF_TSBK_Ctrl_MBF(TSBK_OSP_IDEN_UP);
-
-    if (alt) {
-        // write rfss-net-rfss bcast
-        queueRF_TSBK_Ctrl_MBF(TSBK_OSP_RFSS_STS_BCAST);
-        queueRF_TSBK_Ctrl_MBF(TSBK_OSP_NET_STS_BCAST);
-        queueRF_TSBK_Ctrl_MBF(TSBK_OSP_RFSS_STS_BCAST);
-    }
-    else {
-        // write net-rfss-net bcast
-        queueRF_TSBK_Ctrl_MBF(TSBK_OSP_NET_STS_BCAST);
-        queueRF_TSBK_Ctrl_MBF(TSBK_OSP_RFSS_STS_BCAST);
-        queueRF_TSBK_Ctrl_MBF(TSBK_OSP_NET_STS_BCAST);
+    // loop to generate 6 control sequences
+    if (frameCnt == 255U) {
+        seqCnt = 6U;
     }
 
-    queueRF_TSBK_Ctrl_MBF(TSBK_OSP_SNDCP_CH_ANN);
-
-    // LogDebug(LOG_P25, "writeRF_ControlData, before adjSS, mbfCnt = %u", m_mbfCnt);
-
-    // write ADJSS
-    if (adjSS && m_adjSiteTable.size() > 0) {
-        if (m_mbfAdjSSCnt >= m_adjSiteTable.size())
-            m_mbfAdjSSCnt = 0U;
-
-        uint8_t i = 0U;
-        for (auto it = m_adjSiteTable.begin(); it != m_adjSiteTable.end(); ++it) {
-            // no good very bad way of skipping entries...
-            if (i != m_mbfAdjSSCnt) {
-                i++;
-                continue;
-            }
-            else {
-                m_rfTSBK.reset();
-
-                SiteData site = it->second;
-
-                uint8_t cfva = P25_CFVA_CONV | P25_CFVA_NETWORK;
-                if (m_adjSiteUpdateCnt[site.siteId()] == 0U) {
-                    cfva |= P25_CFVA_FAILURE;
-                }
-                else {
-                    cfva |= P25_CFVA_VALID;
-                }
-
-                // transmit adjacent site broadcast
-                m_rfTSBK.setLCO(TSBK_OSP_ADJ_STS_BCAST);
-                m_rfTSBK.setAdjSiteCFVA(cfva);
-                m_rfTSBK.setAdjSiteSysId(site.sysId());
-                m_rfTSBK.setAdjSiteRFSSId(site.rfssId());
-                m_rfTSBK.setAdjSiteId(site.siteId());
-                m_rfTSBK.setAdjSiteChnId(site.channelId());
-                m_rfTSBK.setAdjSiteChnNo(site.channelNo());
+    do
+    {
+        m_rfTSBK.reset();
 
-                m_rfTSBK.setLastBlock(true); // always set last block
-                writeRF_TSDU_MBF();
+        if (m_debug) {
+            LogDebug(LOG_P25, "writeRF_ControlData, mbfCnt = %u, frameCnt = %u, seq = %u, adjSS = %u", m_mbfCnt, frameCnt, n, adjSS);
+        }
 
-                m_mbfAdjSSCnt++;
-                break;
+        switch (n)
+        {
+        case 0:
+            queueRF_TSBK_Ctrl_MBF(TSBK_OSP_IDEN_UP);
+            break;
+        case 1:
+            queueRF_TSBK_Ctrl_MBF(TSBK_OSP_RFSS_STS_BCAST);
+            break;
+        case 2:
+            queueRF_TSBK_Ctrl_MBF(TSBK_OSP_NET_STS_BCAST);
+            break;
+        case 3:
+            queueRF_TSBK_Ctrl_MBF(TSBK_OSP_SNDCP_CH_ANN);
+            break;
+        case 4:
+            // write ADJSS
+            if (adjSS) {
+                queueRF_TSBK_Ctrl_MBF(TSBK_OSP_ADJ_STS_BCAST);
             }
+            break;
         }
-    }
-
-    // LogDebug(LOG_P25, "writeRF_ControlData, after adjSS, mbfCnt = %u", m_mbfCnt);
+        
+        if (seqCnt > 0U)
+            n++;
+        i++;
+    } while (i <= seqCnt);
 
     // should we insert the BSI bursts?
-    bool bsi = (frameCnt % 127) == 0U;
-    if (bsi) {
+    bool bsi = (frameCnt % 64U) == 0U;
+    if (bsi || frameCnt == 255U) {
         queueRF_TSBK_Ctrl_MBF(TSBK_OSP_MOT_CC_BSI);
-
-        m_rfTSBK.reset();
-
-        // transmit CC BSI burst
-        m_rfTSBK.setLCO(TSBK_OSP_MOT_CC_BSI);
-        m_rfTSBK.setMFId(P25_MFG_MOT);
-
-        m_rfTSBK.setLastBlock(true); // always set last block
-        writeRF_TSDU_MBF();
     }
 
-    // pad MBF if we have 1 queued TSDUs
-    if (m_mbfCnt == 1U) {
-        queueRF_TSBK_Ctrl_MBF(TSBK_OSP_RFSS_STS_BCAST);
-        queueRF_TSBK_Ctrl_MBF(TSBK_OSP_NET_STS_BCAST);
-        if (m_debug) {
-            LogDebug(LOG_P25, "writeRF_ControlData, have 1 pad 2, mbfCnt = %u", m_mbfCnt);
-        }
-    }
-
-    // pad MBF if we have 2 queued TSDUs
-    if (m_mbfCnt == 2U) {
-        std::vector<lookups::IdenTable> entries = m_p25->m_idenTable->list();
-        if (entries.size() > 1U) {
-            queueRF_TSBK_Ctrl_MBF(TSBK_OSP_IDEN_UP);
-        }
-        else {
+    // add padding after the 4th sequence
+    if (seqCnt > 4U) {
+        // pad MBF if we have 1 queued TSDUs
+        if (m_mbfCnt == 1U) {
             queueRF_TSBK_Ctrl_MBF(TSBK_OSP_RFSS_STS_BCAST);
+            queueRF_TSBK_Ctrl_MBF(TSBK_OSP_NET_STS_BCAST);
+            if (m_debug) {
+                LogDebug(LOG_P25, "writeRF_ControlData, have 1 pad 2, mbfCnt = %u", m_mbfCnt);
+            }
         }
-        if (m_debug) {
-            LogDebug(LOG_P25, "writeRF_ControlData, have 2 pad 1, mbfCnt = %u", m_mbfCnt);
+
+        // pad MBF if we have 2 queued TSDUs
+        if (m_mbfCnt == 2U) {
+            std::vector<lookups::IdenTable> entries = m_p25->m_idenTable->list();
+            if (entries.size() > 1U) {
+                queueRF_TSBK_Ctrl_MBF(TSBK_OSP_IDEN_UP);
+            }
+            else {
+                queueRF_TSBK_Ctrl_MBF(TSBK_OSP_RFSS_STS_BCAST);
+            }
+
+            if (m_debug) {
+                LogDebug(LOG_P25, "writeRF_ControlData, have 2 pad 1, mbfCnt = %u", m_mbfCnt);
+            }
         }
-    }
 
-    // reset MBF count
-    m_mbfCnt = 0U;
+        // reset MBF count
+        m_mbfCnt = 0U;
+    }
 }
 
 /// <summary>
@@ -1669,6 +1693,10 @@ void TrunkPacket::queueRF_TSBK_Ctrl_MBF(uint8_t lco)
     switch (lco) {
         case TSBK_OSP_IDEN_UP:
             {
+                if (m_debug) {
+                    LogMessage(LOG_RF, P25_TSDU_STR ", TSBK_OSP_IDEN_UP (Identity Update)");
+                }
+
                 std::vector<lookups::IdenTable> entries = m_p25->m_idenTable->list();
                 if (m_mbfIdenCnt >= entries.size())
                     m_mbfIdenCnt = 0U;
@@ -1723,6 +1751,52 @@ void TrunkPacket::queueRF_TSBK_Ctrl_MBF(uint8_t lco)
             // transmit rfss status burst
             m_rfTSBK.setLCO(TSBK_OSP_RFSS_STS_BCAST);
             break;
+        case TSBK_OSP_ADJ_STS_BCAST:
+            // write ADJSS
+            if (m_adjSiteTable.size() > 0) {
+                if (m_mbfAdjSSCnt >= m_adjSiteTable.size())
+                    m_mbfAdjSSCnt = 0U;
+
+                if (m_debug) {
+                    LogMessage(LOG_RF, P25_TSDU_STR ", TSBK_OSP_ADJ_STS_BCAST (Adjacent Site Broadcast)");
+                }
+
+                uint8_t i = 0U;
+                for (auto it = m_adjSiteTable.begin(); it != m_adjSiteTable.end(); ++it) {
+                    // no good very bad way of skipping entries...
+                    if (i != m_mbfAdjSSCnt) {
+                        i++;
+                        continue;
+                    }
+                    else {
+                        SiteData site = it->second;
+
+                        uint8_t cfva = P25_CFVA_CONV | P25_CFVA_NETWORK;
+                        if (m_adjSiteUpdateCnt[site.siteId()] == 0U) {
+                            cfva |= P25_CFVA_FAILURE;
+                        }
+                        else {
+                            cfva |= P25_CFVA_VALID;
+                        }
+
+                        // transmit adjacent site broadcast
+                        m_rfTSBK.setLCO(TSBK_OSP_ADJ_STS_BCAST);
+                        m_rfTSBK.setAdjSiteCFVA(cfva);
+                        m_rfTSBK.setAdjSiteSysId(site.sysId());
+                        m_rfTSBK.setAdjSiteRFSSId(site.rfssId());
+                        m_rfTSBK.setAdjSiteId(site.siteId());
+                        m_rfTSBK.setAdjSiteChnId(site.channelId());
+                        m_rfTSBK.setAdjSiteChnNo(site.channelNo());
+
+                        m_mbfAdjSSCnt++;
+                        break;
+                    }
+                }
+            }
+            else {
+                return; // don't create anything
+            }
+            break;
         case TSBK_OSP_SNDCP_CH_ANN:
             if (m_debug) {
                 LogMessage(LOG_RF, P25_TSDU_STR ", TSBK_OSP_SNDCP_CH_ANN (SNDCP Channel Announcement)");
@@ -1880,7 +1954,7 @@ void TrunkPacket::writeRF_TSDU_UU_Ans_Req(uint32_t srcId, uint32_t dstId)
     m_rfTSBK.setSrcId(srcId);
     m_rfTSBK.setDstId(dstId);
     m_rfTSBK.setVendorSkip(true);
-    writeRF_TSDU_SBF(true);
+    writeRF_TSDU_SBF(false);
 
     m_rfTSBK.setLCO(lco);
     m_rfTSBK.setVendorSkip(false);
@@ -1929,7 +2003,7 @@ void TrunkPacket::writeRF_TSDU_Deny(uint8_t reason, uint8_t service)
     m_rfTSBK.setLCO(TSBK_OSP_DENY_RSP);
     m_rfTSBK.setService(service);
     m_rfTSBK.setResponse(reason);
-    writeRF_TSDU_SBF(true);
+    writeRF_TSDU_SBF(false);
 
     m_rfTSBK.setLCO(lco);
 }
@@ -1939,8 +2013,10 @@ void TrunkPacket::writeRF_TSDU_Deny(uint8_t reason, uint8_t service)
 /// </summary>
 /// <param name="srcId"></param>
 /// <param name="dstId"></param>
-void TrunkPacket::writeRF_TSDU_Grp_Aff_Rsp(uint32_t srcId, uint32_t dstId)
+bool TrunkPacket::writeRF_TSDU_Grp_Aff_Rsp(uint32_t srcId, uint32_t dstId)
 {
+    bool ret = false;
+
     m_rfTSBK.setLCO(TSBK_IOSP_GRP_AFF);
     m_rfTSBK.setResponse(P25_RSP_ACCEPT);
     m_rfTSBK.setPatchSuperGroupId(m_patchSuperGroup);
@@ -1972,12 +2048,14 @@ void TrunkPacket::writeRF_TSDU_Grp_Aff_Rsp(uint32_t srcId, uint32_t dstId)
         }
 
         ::ActivityLog("P25", true, "received group affiliation request from %u to %s %u", srcId, "TG ", dstId);
+        ret = true;
 
         // update dynamic affiliation table
         m_grpAffTable[srcId] = dstId;
     }
 
     writeRF_TSDU_SBF(false);
+    return ret;
 }
 
 /// <summary>
@@ -2059,6 +2137,7 @@ void TrunkPacket::writeRF_TSDU_U_Dereg_Ack(uint32_t srcId)
     }
 
     m_rfTSBK.setSrcId(P25_WUID_SYS);
+    m_rfTSBK.setDstId(srcId);
 
     writeRF_TSDU_SBF(false);
 }
@@ -2080,7 +2159,7 @@ void TrunkPacket::writeRF_TSDU_Queue(uint8_t reason, uint8_t service)
     m_rfTSBK.setLCO(TSBK_OSP_QUE_RSP);
     m_rfTSBK.setService(service);
     m_rfTSBK.setResponse(reason);
-    writeRF_TSDU_SBF(true);
+    writeRF_TSDU_SBF(false);
 
     m_rfTSBK.setLCO(lco);
 }
diff --git a/p25/TrunkPacket.h b/p25/TrunkPacket.h
index ddd511e4..267c8910 100644
--- a/p25/TrunkPacket.h
+++ b/p25/TrunkPacket.h
@@ -100,6 +100,8 @@ namespace p25
         void touchDstIdGrant(uint32_t dstId);
         /// <summary>Helper to release the channel grant for the destination ID.</summary>
         void releaseDstIdGrant(uint32_t dstId, bool releaseAll);
+        /// <summary>Helper to release group affiliations.</summary>
+        void clearGrpAff(uint32_t dstId, bool releaseAll);
 
         /// <summary></summary>
         void resetStatusCommand();
@@ -191,7 +193,7 @@ namespace p25
         void writeNetworkRF(const uint8_t* data, bool autoReset);
 
         /// <summary>Helper to write control channel packet data.</summary>
-        void writeRF_ControlData(uint8_t frameCnt, bool adjSS);
+        void writeRF_ControlData(uint8_t frameCnt, uint8_t n, bool adjSS);
 
         /// <summary>Helper to write a P25 TDU w/ link control packet.</summary>
         void writeRF_TDULC(uint8_t duid, bool noNetwork);
@@ -217,7 +219,7 @@ namespace p25
         /// <summary>Helper to write a deny packet.</summary>
         void writeRF_TSDU_Deny(uint8_t reason, uint8_t service);
         /// <summary>Helper to write a group affiliation response packet.</summary>
-        void writeRF_TSDU_Grp_Aff_Rsp(uint32_t srcId, uint32_t dstId);
+        bool writeRF_TSDU_Grp_Aff_Rsp(uint32_t srcId, uint32_t dstId);
         /// <summary>Helper to write a unit registration response packet.</summary>
         void writeRF_TSDU_U_Reg_Rsp(uint32_t srcId);
         /// <summary>Helper to write a unit de-registration acknowledge packet.</summary>
diff --git a/p25/VoicePacket.cpp b/p25/VoicePacket.cpp
index 1bbde575..58b71430 100644
--- a/p25/VoicePacket.cpp
+++ b/p25/VoicePacket.cpp
@@ -129,7 +129,7 @@ bool VoicePacket::process(uint8_t* data, uint32_t len)
             m_p25->writeRF_Preamble();
 
             if (!m_p25->m_ccRunning) {
-                m_p25->m_trunk->writeRF_ControlData(127U, false);
+                m_p25->m_trunk->writeRF_ControlData(255U, 0U, false);
             }
         }
 
@@ -235,6 +235,16 @@ bool VoicePacket::process(uint8_t* data, uint32_t len)
                 // if the group wasn't granted out -- explicitly grant the group
                 if (!m_p25->m_trunk->hasDstIdGranted(dstId)) {
                     if (m_p25->m_legacyGroupGrnt) {
+                        // are we auto-registering legacy radios to groups?
+                        if (m_p25->m_legacyGroupReg && m_rfLC.getGroup()) {
+                            if (!m_p25->m_trunk->hasSrcIdGrpAff(srcId, dstId)) {
+                                m_p25->m_trunk->m_skipSBFPreamble = true; // HACK: force an SBF to skip generating preambles
+                                if (!m_p25->m_trunk->writeRF_TSDU_Grp_Aff_Rsp(srcId, dstId)) {
+                                    return false;
+                                }
+                            }
+                        }                        
+
                         m_p25->m_trunk->m_skipSBFPreamble = true; // HACK: force an SBF to skip generating preambles
                         if (!m_p25->m_trunk->writeRF_TSDU_Grant(m_rfLC.getGroup(), false)) {
                             return false;
@@ -693,7 +703,7 @@ bool VoicePacket::processNetwork(uint8_t* data, uint32_t len, lc::LC& control, d
                     m_p25->m_trunk->resetNet();
 
                     if (!m_p25->m_ccRunning) {
-                        m_p25->m_trunk->writeRF_ControlData(127U, false);
+                        m_p25->m_trunk->writeRF_ControlData(255U, 0U, false);
                     }
 
                     writeNet_HDU(control, lsd);
@@ -740,7 +750,7 @@ bool VoicePacket::writeEndRF()
         writeRF_EndOfVoice();
 
         if (!m_p25->m_ccRunning) {
-            m_p25->m_trunk->writeRF_ControlData(127U, false);
+            m_p25->m_trunk->writeRF_ControlData(255U, 0U, false);
             m_p25->writeControlEndRF();
         }
 
diff --git a/p25/lc/TSBK.cpp b/p25/lc/TSBK.cpp
index b5722106..08badb8f 100644
--- a/p25/lc/TSBK.cpp
+++ b/p25/lc/TSBK.cpp
@@ -156,6 +156,8 @@ bool TSBK::decode(const uint8_t* data)
         case TSBK_IOSP_U_REG:
         case TSBK_ISP_CAN_SRV_REQ:
         case TSBK_ISP_GRP_AFF_Q_RSP:
+        case TSBK_OSP_DENY_RSP:
+        case TSBK_OSP_QUE_RSP:
         case TSBK_ISP_U_DEREG_REQ:
         case TSBK_OSP_U_DEREG_ACK:
         case TSBK_ISP_LOC_REG_REQ:
@@ -252,6 +254,14 @@ bool TSBK::decode(const uint8_t* data)
         m_dstId = (uint32_t)((tsbkValue >> 24) & 0xFFFFU);                          // Talkgroup Address
         m_srcId = (uint32_t)(tsbkValue & 0xFFFFFFU);                                // Source Radio Address
         break;
+    case TSBK_OSP_DENY_RSP:
+    case TSBK_OSP_QUE_RSP:
+        m_aivFlag = (((tsbkValue >> 56) & 0xFFU) & 0x80U) == 0x80U;                 // Additional Info. Flag
+        m_service = (uint8_t)((tsbkValue >> 56) & 0x3FU);                           // Service Type
+        m_response = (uint8_t)((tsbkValue >> 48) & 0xFFU);                          // Reason
+        m_dstId = (uint32_t)((tsbkValue >> 24) & 0xFFFFFFU);                        // Target Radio Address
+        m_srcId = (uint32_t)(tsbkValue & 0xFFFFFFU);                                // Source Radio Address
+        break;
     case TSBK_ISP_U_DEREG_REQ:
     case TSBK_OSP_U_DEREG_ACK:
         m_netId = (uint32_t)((tsbkValue >> 36) & 0xFFFFFU);                         // Network ID