diff --git a/IO.cpp b/IO.cpp
index 47dd8c5..7508bf5 100644
--- a/IO.cpp
+++ b/IO.cpp
@@ -334,10 +334,10 @@ void CIO::process()
       }
 
       if (m_p25Enable) {
-        q15_t C4FSKVals[RX_BLOCK_SIZE];
-        ::arm_fir_fast_q15(&m_boxcarFilter, dcSamples, C4FSKVals, RX_BLOCK_SIZE);
+        q15_t P25Vals[RX_BLOCK_SIZE];
+        ::arm_fir_fast_q15(&m_boxcarFilter, dcSamples, P25Vals, RX_BLOCK_SIZE);
 
-        p25RX.samples(C4FSKVals, rssi, RX_BLOCK_SIZE);
+        p25RX.samples(P25Vals, rssi, RX_BLOCK_SIZE);
       }
 
       if (m_nxdnEnable) {
diff --git a/NXDNRX.cpp b/NXDNRX.cpp
index eab67dd..e9bd41b 100644
--- a/NXDNRX.cpp
+++ b/NXDNRX.cpp
@@ -23,9 +23,10 @@
 
 const q15_t SCALING_FACTOR = 18750;      // Q15(0.55)
 
-const uint8_t MAX_FSW_BIT_ERRS = 1U;
+const uint8_t MAX_FSW_BIT_START_ERRS = 1U;
+const uint8_t MAX_FSW_BIT_RUN_ERRS   = 3U;
 
-const uint8_t MAX_FSW_SYMBOLS_ERRS = 1U;
+const uint8_t MAX_FSW_SYMBOLS_ERRS = 2U;
 
 const uint8_t BIT_MASK_TABLE[] = {0x80U, 0x40U, 0x20U, 0x10U, 0x08U, 0x04U, 0x02U, 0x01U};
 
@@ -255,11 +256,17 @@ bool CNXDNRX::correlateFSW()
       uint8_t sync[NXDN_FSW_BYTES_LENGTH];
       samplesToBits(startPtr, NXDN_FSW_LENGTH_SYMBOLS, sync, 0U, m_centreVal, m_thresholdVal);
 
-      uint8_t errs = 0U;
+      uint8_t maxErrs;
+      if (m_state == NXDNRXS_NONE)
+        maxErrs = MAX_FSW_BIT_START_ERRS;
+      else
+        maxErrs = MAX_FSW_BIT_RUN_ERRS;
+
+     uint8_t errs = 0U;
       for (uint8_t i = 0U; i < NXDN_FSW_BYTES_LENGTH; i++)
         errs += countBits8((sync[i] & NXDN_FSW_BYTES_MASK[i]) ^ NXDN_FSW_BYTES[i]);
 
-      if (errs <= MAX_FSW_BIT_ERRS) {
+      if (errs <= maxErrs) {
         m_maxCorr   = corr;
         m_lostCount = MAX_FSW_FRAMES;
         m_fswPtr    = m_dataPtr;