okay at least my APX6000 fails authentication now;

src/p25/lc/AMBT.cpp

@@ -165,7 +165,10 @@ void AMBT::encode(data::DataHeader& dataHeader, uint8_t* pduUserData)
     dataHeader.setSAP(PDU_SAP_TRUNK_CTRL);
     dataHeader.setLLId(m_srcId);
     dataHeader.setFullMessage(true);
-    dataHeader.setBlocksToFollow(1U);
+
+    if (dataHeader.getBlocksToFollow() == 0U) {
+        dataHeader.setBlocksToFollow(1U);
+    }
 
     dataHeader.setAMBTOpcode(m_lco);
 

src/p25/packet/ControlSignaling.cpp

@@ -2864,7 +2864,8 @@ bool ControlSignaling::writeRF_TSDU_Loc_Reg_Rsp(uint32_t srcId, uint32_t dstId,
 void ControlSignaling::writeRF_TSDU_Auth_Dmd(uint32_t srcId)
 {
     std::unique_ptr<MBT_OSP_AUTH_DMD> osp = new_unique(MBT_OSP_AUTH_DMD);
-    osp->setSrcId(srcId);
+    osp->setSrcId(P25_WUID_FNE);
+    osp->setDstId(srcId);
     osp->setAuthRS(m_p25->m_llaRS);
 
     // generate challenge