diff --git a/demod/multi/demod_base.c b/demod/multi/demod_base.c
index 3e39b1f..dea34a6 100644
--- a/demod/multi/demod_base.c
+++ b/demod/multi/demod_base.c
@@ -932,18 +932,20 @@ static int headcmp(dsp_t *dsp, int opt_dc) {
 
     //if (opt_dc == 0 || dsp->opt_iq > 1) dsp->dc = 0; // reset? e.g. 2nd pass
 
-    if (dsp->symhd != 1) step = 2;
+    if (dsp->symhd != 1) step = 2; // step == symhd
     if (inv) sign=1;
 
     for (pos = 0; pos < len; pos++) {                  // L = dsp->hdrlen * dsp->sps + 0.5;
         //read_bufbit(dsp, dsp->symhd, dsp->rawbits+pos*step, mvp+1-(int)(len*dsp->sps), pos);
         read_bufbit(dsp, dsp->symhd, dsp->rawbits+pos*step, dsp->mv_pos+1-dsp->L, pos);
     }
+
+    pos = len*step; // == hdrlen
     dsp->rawbits[pos] = '\0';
 
-    while (len > 0) {
-        if ((dsp->rawbits[len-1]^sign) != dsp->hdr[len-1]) errs += 1;
-        len--;
+    while (pos > 0) {
+        if ((dsp->rawbits[pos-1]^sign) != dsp->hdr[pos-1]) errs += 1;
+        pos--;
     }
 
     return errs;
diff --git a/demod/multi/dfm09base.c b/demod/multi/dfm09base.c
index 538c49a..5a66ceb 100644
--- a/demod/multi/dfm09base.c
+++ b/demod/multi/dfm09base.c
@@ -99,7 +99,7 @@ typedef struct {
     double dir; double horiV; double vertV;
     double lat2; double lon2; double alt2;
     double dir2; double horiV2; double vertV2;
-    //float T;
+    float T;
     float Rf;
     float _frmcnt;
     float meas24[9];
@@ -615,6 +615,7 @@ static int reset_cfgchk(gpx_t *gpx) {
     gpx->ptu_out = 0;
     //gpx->gps.dMSL = 0;
     *gpx->SN_out = '\0';
+    gpx->T = -273.15f;
     return 0;
 }
 
@@ -871,6 +872,18 @@ static int print_gpx(gpx_t *gpx) {
             gpx->prev_cntsec_diff = cntsec_diff;
             gpx->prev_manpol = gpx->option.inv;
         }
+
+        gpx->T = -273.15f;
+        if (gpx->cfgchk && gpx->ptu_out)
+        {
+            gpx->T = get_Temp(gpx);
+            if (gpx->T < -270.0f && gpx->dfmtyp != DFM_types[UNDEF]) {
+                if ((gpx->sonde_typ & 0xF) == 0x8 || (gpx->sonde_typ & 0xF) == 0xC)
+                {
+                    gpx->dfmtyp = DFM_types[UNKNW];
+                }
+            }
+        }
     }
 
     if (output & 0xF000) {
@@ -902,16 +915,16 @@ static int print_gpx(gpx_t *gpx) {
             if (gpx->cfgchk)
             {
                 if (gpx->option.ptu  &&  gpx->ptu_out) {
-                    float t = get_Temp(gpx);
-                    if (t > -270.0) {
-                        printf("  T=%.1fC ", t);     // 0xC:P+ DFM-09P , 0xC:T- DFM-17TU , 0xD:P- DFM-17P ?
+                    //float t = get_Temp(gpx);
+                    if (gpx->T > -270.0f) {
+                        printf("  T=%.1fC ", gpx->T);     // 0xC:P+ DFM-09P , 0xC:T- DFM-17TU , 0xD:P- DFM-17P ?
                         if (gpx->option.vbs == 3) printf(" (0x%X:%c%c) ", gpx->sonde_typ & 0xF, gpx->sensortyp, gpx->option.inv?'-':'+');
                     }
                     if (gpx->option.dbg) {
                         float t2 = get_Temp2(gpx);
                         float t4 = get_Temp4(gpx);
-                        if (t2 > -270.0) printf("  T2=%.1fC ", t2);
-                        if (t4 > -270.0) printf(" T4=%.1fC  ", t4);
+                        if (t2 > -270.0f) printf("  T2=%.1fC ", t2);
+                        if (t4 > -270.0f) printf(" T4=%.1fC  ", t4);
                     }
                 }
                 if (gpx->option.vbs == 3  &&  gpx->ptu_out >= 0xA) {
@@ -1013,8 +1026,8 @@ static int print_gpx(gpx_t *gpx) {
                 printf(", \"batt\": %.2f", gpx->status[0]);
             }
             if (gpx->ptu_out) { // get temperature
-                float t = get_Temp(gpx); // ecc-valid temperature?
-                if (t > -270.0) printf(", \"temp\": %.1f", t);
+                //float t = get_Temp(gpx); // ecc-valid temperature?
+                if (gpx->T > -270.0f) printf(", \"temp\": %.1f", gpx->T);
             }
             if (gpx->posmode == 4 && contaux && gpx->xdata[0]) {
                 char xdata_str[2*XDATA_LEN+1];
diff --git a/demod/multi/m10base.c b/demod/multi/m10base.c
index 1afc4a6..99aa83a 100644
--- a/demod/multi/m10base.c
+++ b/demod/multi/m10base.c
@@ -1102,7 +1102,7 @@ static int print_frame(gpx_t *gpx, int pos, dsp_t *dsp) {
             }
             fprintf(stdout, "\n");
         }
-        if (gpx->option.slt /*&& gpx->option.jsn*/) {
+        if (gpx->frame_bytes[1] != 0x49 && gpx->option.slt /*&& gpx->option.jsn*/) {
             print_pos(gpx, cs1 == cs2);
         }
     }
@@ -1112,6 +1112,7 @@ static int print_frame(gpx_t *gpx, int pos, dsp_t *dsp) {
                 byte = gpx->frame_bytes[i];
                 fprintf(stdout, "%02x", byte);
             }
+            if (cs1 == cs2) fprintf(stdout, " [OK]"); else fprintf(stdout, " [NO]");
             fprintf(stdout, "\n");
         }
     }
diff --git a/demod/multi/m20base.c b/demod/multi/m20base.c
index d2ff67c..52f7d7f 100644
--- a/demod/multi/m20base.c
+++ b/demod/multi/m20base.c
@@ -921,7 +921,7 @@ static int print_frame(gpx_t *gpx, int pos, dsp_t *dsp) {
             }
             fprintf(stdout, "\n");
         }
-        if (gpx->option.slt /*&& gpx->option.jsn*/) {
+        if (gpx->option.slt /*&& gpx->option.jsn && gpx->frame_bytes[1] != 0x49*/) {
             print_pos(gpx, bc, cs1 == cs2);
         }
     }
@@ -932,6 +932,7 @@ static int print_frame(gpx_t *gpx, int pos, dsp_t *dsp) {
                 byte = gpx->frame_bytes[i];
                 fprintf(stdout, "%02x", byte);
             }
+            if (cs1 == cs2) fprintf(stdout, " [OK]"); else fprintf(stdout, " [NO]");
             fprintf(stdout, "\n");
         }
     }