diff --git a/src/jtagmkI.c b/src/jtagmkI.c
index 48d51efb..856ca14a 100644
--- a/src/jtagmkI.c
+++ b/src/jtagmkI.c
@@ -1085,16 +1085,22 @@ static int jtagmkI_get_sck_period(const PROGRAMMER *pgm, double *v) {
     *v = 500e3;
   else if (dur == JTAG_BITRATE_250_kHz)
     *v = 250e3;
-  else
+  else if (dur == JTAG_BITRATE_125_kHz)
     *v = 125e3;
+  else { // something went wrong
+    pmsg_error("wrong JTAG_BITRATE ID %02X\n", dur);
+    return -1;
+  }
   return 0;
 }
 
 
 static int jtagmkI_get_vtarget(const PROGRAMMER *pgm, double *v) {
   unsigned char vtarget = 0;
-  if (jtagmkI_getparm(pgm, PARM_OCD_VTARGET, &vtarget) < 0)
-    return - 1;
+  if (jtagmkI_getparm(pgm, PARM_OCD_VTARGET, &vtarget) < 0) {
+    pmsg_error("jtagmkI_getparm PARM_OCD_VTARGET failed\n");
+    return -1;
+  }
   *v = 6.25 * (unsigned)vtarget / 255.0;
   return 0;
 }
diff --git a/src/stk500.c b/src/stk500.c
index 673c10f3..aafcccf4 100644
--- a/src/stk500.c
+++ b/src/stk500.c
@@ -1190,8 +1190,10 @@ static int stk500_set_vtarget(const PROGRAMMER *pgm, double v) {
 
   if (uaref > utarg) {
     pmsg_warning("reducing V[aref] from %.1f to %.1f\n", uaref / 10.0, v);
-    if ((rc = stk500_setparm(pgm, Parm_STK_VADJUST, utarg)) != 0)
+    if ((rc = stk500_setparm(pgm, Parm_STK_VADJUST, utarg)) != 0) {
+      pmsg_error("cannot set V[aref]\n");
       return rc;
+    }
   }
   return stk500_setparm(pgm, Parm_STK_VTARGET, utarg);
 }
@@ -1228,7 +1230,10 @@ static int stk500_set_varef(const PROGRAMMER *pgm, unsigned int chan /* unused *
       "V[target] = %.1f\n", utarg/10.0);
     return -1;
   }
-  return stk500_setparm(pgm, Parm_STK_VADJUST, uaref);
+
+  if ((rc = stk500_setparm(pgm, Parm_STK_VADJUST, uaref)) < 0)
+    pmsg_error("cannot set V[aref]\n");
+  return rc;
 }
 
 
@@ -1253,7 +1258,7 @@ static int stk500_set_fosc(const PROGRAMMER *pgm, double v) {
     1, 8, 32, 64, 128, 256, 1024
   };
   size_t idx;
-  int rc;
+  int rc = 0;
 
   prescale = cmatch = 0;
   if (v > 0.0) {
@@ -1287,31 +1292,39 @@ static int stk500_set_fosc(const PROGRAMMER *pgm, double v) {
     }
   }
   
-  if ((rc = stk500_setparm(pgm, Parm_STK_OSC_PSCALE, prescale)) != 0
-      || (rc = stk500_setparm(pgm, Parm_STK_OSC_CMATCH, cmatch)) != 0)
+  if ((rc = stk500_setparm(pgm, Parm_STK_OSC_PSCALE, prescale)) != 0 ) {
+    pmsg_error("cannot set Parm_STK_OSC_PSCALE\n");
     return rc;
-  
+  }
+
+  if ((rc = stk500_setparm(pgm, Parm_STK_OSC_CMATCH, cmatch)) != 0) {
+    pmsg_error("cannot set Parm_STK_OSC_CMATCH\n");
+    return rc;
+  }
+
   return 0;
 }
 
 
 static int stk500_get_fosc(const PROGRAMMER *pgm, double *v) {
   unsigned prescale=0, cmatch=0;
-  double fosc = 0;
   static unsigned ps[] = {
     1, 8, 32, 64, 128, 256, 1024
   };
   int rc;
 
-  if ((rc = stk500_getparm(pgm, Parm_STK_OSC_PSCALE, &prescale)) != 0
-      || (rc = stk500_getparm(pgm, Parm_STK_OSC_CMATCH, &cmatch)) != 0)
+  if ((rc = stk500_getparm(pgm, Parm_STK_OSC_PSCALE, &prescale)) != 0) {
+    pmsg_error("cannot get Parm_STK_OSC_PSCALE\n");
     return rc;
+}
+
+  if ((rc = stk500_getparm(pgm, Parm_STK_OSC_CMATCH, &cmatch)) != 0) {
+    pmsg_error("cannot get Parm_STK_OSC_CMATCH\n");
+    return rc;
+  }
+
+  *v = !prescale ? 0 : PDATA(pgm)->xtal / ((cmatch + 1) * 2 * ps[prescale - 1]);
 
-  if (prescale) {
-  fosc = PDATA(pgm)->xtal / ((cmatch + 1) * 2 * ps[prescale - 1]);
-  } else
-    fosc = 0;
-  *v = fosc;
   return 0;
 }
 
@@ -1326,11 +1339,12 @@ static int stk500_get_fosc(const PROGRAMMER *pgm, double *v) {
 static int stk500_set_sck_period(const PROGRAMMER *pgm, double v) {
   int dur;
   double min, max;
+  int rv = 0;
 
   min = 8.0 / PDATA(pgm)->xtal;
   max = 255 * min;
   dur = v / min + 0.5;
-  
+
   if (v < min) {
       dur = 1;
       pmsg_warning("p = %.1f us too small, using %.1f us\n",
@@ -1340,8 +1354,12 @@ static int stk500_set_sck_period(const PROGRAMMER *pgm, double v) {
       pmsg_warning("p = %.1f us too large, using %.1f us\n",
         v/1e-6, dur*min/1e-6);
   }
-  
-  return stk500_setparm(pgm, Parm_STK_SCK_DURATION, dur);
+
+  if ((rv = stk500_setparm(pgm, Parm_STK_SCK_DURATION, dur)) < 0) {
+    pmsg_error("cannot set Parm_STK_SCK_DURATION\n");
+    return rv;
+  }
+  return 0;
 }
 
 
@@ -1349,8 +1367,8 @@ static int stk500_get_sck_period(const PROGRAMMER *pgm, double *v) {
   unsigned dur;
   int rv = 0;
 
-  if ((rv = stk500_getparm(pgm, Parm_STK_SCK_DURATION, &dur))< 0) {
-    pmsg_error("cannot obtain sck duration\n");
+  if ((rv = stk500_getparm(pgm, Parm_STK_SCK_DURATION, &dur)) < 0) {
+    pmsg_error("cannot obtain Parm_STK_SCK_DURATION\n");
     return rv;
   }
   *v = dur * 8.0 / PDATA(pgm)->xtal;
diff --git a/src/stk500v2.c b/src/stk500v2.c
index 56811024..259e24aa 100644
--- a/src/stk500v2.c
+++ b/src/stk500v2.c
@@ -301,10 +301,7 @@ void stk500v2_setup(PROGRAMMER * pgm)
   memset(pgm->cookie, 0, sizeof(struct pdata));
   PDATA(pgm)->command_sequence = 1;
   PDATA(pgm)->boot_start = ULONG_MAX;
-  if (str_starts(pgmid, "scratchmonkey"))
-    PDATA(pgm)->xtal = SCRATCHMONKEY_XTAL;
-  else
-    PDATA(pgm)->xtal = STK500V2_XTAL;
+  PDATA(pgm)->xtal = str_starts(pgmid, "scratchmonkey") ? SCRATCHMONKEY_XTAL : STK500V2_XTAL;
 }
 
 static void stk500v2_jtagmkII_setup(PROGRAMMER * pgm)
@@ -3719,11 +3716,14 @@ static double stk500v2_vtarget_value(const PROGRAMMER *pgm) {
     jtagmkII_getparm(pgmcp, PAR_OCD_VTARGET, vtarget_jtag);
     pgm_free(pgmcp);
     return b2_to_u16(vtarget_jtag) / 1000.0;
-  } else if (PDATA(pgm)->pgmtype != PGMTYPE_JTAGICE3) {
+  }
+
+  if (PDATA(pgm)->pgmtype != PGMTYPE_JTAGICE3) {
     unsigned char vtarget = 0;
     stk500v2_getparm(pgm, PARAM_VTARGET, &vtarget);
     return vtarget / 10.0;
   }
+
   return 0;
 }
 
@@ -3736,13 +3736,11 @@ static double stk500v2_sck_duration_value(const PROGRAMMER *pgm) {
   case PGMTYPE_STK500:
     stk500v2_getparm(pgm, PARAM_SCK_DURATION, &sck_duration);
     return stk500v2_sck_to_us(pgm, sck_duration);
-    break;
 
   case PGMTYPE_AVRISP_MKII:
   case PGMTYPE_JTAGICE_MKII:
     stk500v2_getparm(pgm, PARAM_SCK_DURATION, &sck_duration);
     return 1.0e6 / avrispmkIIfreqs[sck_duration];
-    break;
 
   case PGMTYPE_JTAGICE3:
     {
@@ -3754,16 +3752,13 @@ static double stk500v2_sck_duration_value(const PROGRAMMER *pgm) {
       }
       return 0;
     }
-    break;
 
   case PGMTYPE_STK600:
     stk500v2_getparm2(pgm, PARAM2_SCK_DURATION, &sck_stk600);
     return (sck_stk600 + 1) / 8.0;
-    break;
 
   default:
     return sck_duration * 8.0e6 / PDATA(pgm)->xtal + 0.05;
-    break;
   }
   return 0;
 }
@@ -3771,7 +3766,6 @@ static double stk500v2_sck_duration_value(const PROGRAMMER *pgm) {
 
 static double stk500v2_varef_value(const PROGRAMMER *pgm) {
   unsigned char vadjust = 0;
-
   if (stk500v2_getparm(pgm, PARAM_VADJUST, &vadjust) < 0)
     return 0;
   return vadjust / 10.0;
@@ -3808,30 +3802,27 @@ static double stk500v2_fosc_value(const PROGRAMMER *pgm) {
       return 0.0;
     if (osc_pscale == 0)
       return 0.0;
-    else {
-      prescale = 1;
-      fosc = PDATA(pgm)->xtal / 2;
 
-      switch (osc_pscale) {
-        case 2: prescale = 8; break;
-        case 3: prescale = 32; break;
-        case 4: prescale = 64; break;
-        case 5: prescale = 128; break;
-        case 6: prescale = 256; break;
-        case 7: prescale = 1024; break;
-      }
-      fosc /= prescale;
-      fosc /= (osc_cmatch + 1);
-      return fosc;
+    prescale = 1;
+    fosc = PDATA(pgm)->xtal / 2;
+
+    switch (osc_pscale) {
+      case 2: prescale = 8; break;
+      case 3: prescale = 32; break;
+      case 4: prescale = 64; break;
+      case 5: prescale = 128; break;
+      case 6: prescale = 256; break;
+      case 7: prescale = 1024; break;
     }
-    break;
+    fosc /= prescale;
+    fosc /= (osc_cmatch + 1);
+    return fosc;
 
   case PGMTYPE_AVRISP_MKII:
   case PGMTYPE_JTAGICE_MKII:
     if (stk500v2_getparm(pgm, PARAM_SCK_DURATION, &sck_duration) < 0)
       return 0.0;
     return 1e6 / avrispmkIIfreqs[sck_duration];
-    break;
 
   case PGMTYPE_STK600:
     if (stk500v2_getparm2(pgm, PARAM2_CLOCK_CONF, &clock_conf) < 0)
@@ -3840,14 +3831,10 @@ static double stk500v2_fosc_value(const PROGRAMMER *pgm) {
     dac = (clock_conf & 0x0ffc) >> 2u;
     fosc = pow(2, (double)oct) * 2078.0 / (2 - (double)dac / 1024.0);
     return fosc;
-    break;
 
   default:
     return 0.0;
-    break;
   }
-
-  return 0.0;
 }
 
 
@@ -3887,7 +3874,7 @@ static void stk500v2_print_parms1(const PROGRAMMER *pgm, const char *p, FILE *fp
 
   case PGMTYPE_AVRISP_MKII:
   case PGMTYPE_JTAGICE_MKII:
-    fmsg_out(fp, "%sSCK period      : %.2f us\n", p, stk500v2_sck_duration_value(pgm));
+    fmsg_out(fp, "%sSCK period            : %.1f us\n", p, stk500v2_sck_duration_value(pgm));
     break;
 
   case PGMTYPE_JTAGICE3:
@@ -3896,7 +3883,7 @@ static void stk500v2_print_parms1(const PROGRAMMER *pgm, const char *p, FILE *fp
       cmd[0] = CMD_GET_SCK;
       if (stk500v2_jtag3_send(pgm, cmd, 1) >= 0 && stk500v2_jtag3_recv(pgm, cmd, 4) >= 2) {
 	      unsigned int sck = cmd[1] | (cmd[2] << 8);
-	      fmsg_out(fp, "%sSCK period            : %.2f us\n", p, (1E6 / (1000.0 * sck)));
+	      fmsg_out(fp, "%sSCK period            : %.1f us\n", p, (1E6 / (1000.0 * sck)));
       }
       PROGRAMMER *pgmcp = pgm_dup(pgm);
       pgmcp->cookie = PDATA(pgm)->chained_pdata;
@@ -3911,10 +3898,10 @@ static void stk500v2_print_parms1(const PROGRAMMER *pgm, const char *p, FILE *fp
 
   case PGMTYPE_STK600:
     if (pgm->extra_features & HAS_VAREF_ADJ) {
-      fmsg_out(fp, "%sVaref 0         : %.2f V\n", p, stk600_varef_0_value(pgm));
-      fmsg_out(fp, "%sVaref 1         : %.2f V\n", p, stk600_varef_1_value(pgm));
+      fmsg_out(fp, "%sVaref 0               : %.2f V\n", p, stk600_varef_0_value(pgm));
+      fmsg_out(fp, "%sVaref 1               : %.2f V\n", p, stk600_varef_1_value(pgm));
     }
-    fmsg_out(fp, "%sSCK period      : %.2f us\n", p, stk500v2_sck_duration_value(pgm));
+    fmsg_out(fp, "%sSCK period            : %.1f us\n", p, stk500v2_sck_duration_value(pgm));
     if (pgm->extra_features & HAS_FOSC_ADJ) {
       f = stk500v2_sck_duration_value(pgm);
       f = f_to_kHz_MHz(f, &unit);
@@ -3923,7 +3910,7 @@ static void stk500v2_print_parms1(const PROGRAMMER *pgm, const char *p, FILE *fp
     break;
 
   default:
-    fmsg_out(fp, "%sSCK period      : %.1f us\n", p, stk500v2_sck_duration_value(pgm));
+    fmsg_out(fp, "%sSCK period            : %.1f us\n", p, stk500v2_sck_duration_value(pgm));
     break;
   }