diff --git a/mbus/mbus-protocol-aux.c b/mbus/mbus-protocol-aux.c
index ec0f6f0..e655323 100755
--- a/mbus/mbus-protocol-aux.c
+++ b/mbus/mbus-protocol-aux.c
@@ -17,6 +17,7 @@
 
 #include <stdio.h>
 #include <string.h>
+#include <math.h>
 
 #define MBUS_ERROR(...) fprintf (stderr, __VA_ARGS__)
 
@@ -1024,14 +1025,15 @@ mbus_vib_unit_normalize(mbus_value_information_block *vib, double value, char **
                 return -1;
             }
         } 
-        else if (vib->vif == 0x7C)
+        else if ((vib->vif == 0x7C) ||
+                 (vib->vif == 0xFC))
         {
             // custom VIF
             *unit_out = strdup("-");
             *quantity_out = strdup(vib->custom_vif);
-            *value_out = 0.0;
-        } 
-        else 
+            *value_out = value;
+        }
+        else
         {
             int code = (vib->vif) & 0x7f;
             if (0 != mbus_vif_unit_normalize(code, value, unit_out, value_out, quantity_out))
@@ -1041,6 +1043,37 @@ mbus_vib_unit_normalize(mbus_value_information_block *vib, double value, char **
             }
         }
     }
+    
+    if ((vib->vif & MBUS_DIB_VIF_EXTENSION_BIT) &&                       
+        (vib->vif != 0xFD) &&
+        (vib->vif != 0xFB))                       /* codes for VIF extention: see table 8.4.5 */
+    {
+        int code = (vib->vif) & 0x7f;
+        switch (code)
+        {
+            case 0x70:
+            case 0x71:
+            case 0x72:
+            case 0x73:
+            case 0x74:
+            case 0x75:
+            case 0x76:
+            case 0x77: /* Multiplicative correction factor: 10^nnn-6 */
+                *value_out *= pow(10.0, (vib->vife[0] & 0x07) - 6);
+                break;
+                
+            case 0x78:
+            case 0x79:
+            case 0x7A:
+            case 0x7B: /* Additive correction constant: 10^nn-3 unit of VIF (offset) */
+                *value_out += pow(10.0, (vib->vife[0] & 0x03) - 3);
+                break;
+                
+            case 0x7D: /* Multiplicative correction factor: 10^3 */
+                *value_out *= 1000.0;
+                break;
+        }
+    }
 
     return 0;
 }
diff --git a/mbus/mbus-protocol.c b/mbus/mbus-protocol.c
index 91957e7..3c94b16 100755
--- a/mbus/mbus-protocol.c
+++ b/mbus/mbus-protocol.c
@@ -2104,6 +2104,13 @@ mbus_vib_unit_lookup(mbus_value_information_block *vib)
         snprintf(buff, sizeof(buff), "%s", vib->custom_vif);
         return buff;
     }
+    else if (vib->vif == 0xFC && (vib->vife[0] & 0x78) == 0x70)
+    {
+        // custom VIF
+        n = (vib->vife[0] & 0x07);
+        snprintf(buff, sizeof(buff), "%s %s", mbus_unit_prefix(n-6), vib->custom_vif);
+        return buff;
+    }
 
     return mbus_vif_unit_lookup(vib->vif); // no extention, use VIF
 }
@@ -2686,21 +2693,30 @@ mbus_data_variable_parse(mbus_frame *frame, mbus_data_variable *data)
             // read and parse VIB (= VIF + VIFE)
 
             // VIF
-            record->drh.vib.vif = frame->data[i]; 
-                
-            if (record->drh.vib.vif == 0x7C)
+            record->drh.vib.vif = frame->data[i++];
+            
+            if ((record->drh.vib.vif & 0x7F) == 0x7C)
             {
                 // variable length VIF in ASCII format
                 int var_vif_len;
-                i++;
                 var_vif_len = frame->data[i++];
+                if (i + var_vif_len > frame->data_size)
+                {
+                    mbus_data_record_free(record);
+                    return -1;
+                }
                 mbus_data_str_decode(record->drh.vib.custom_vif, &(frame->data[i]), var_vif_len);
                 i += var_vif_len;
             }
-            else
+            
+            // VIFE
+            record->drh.vib.nvife = 0;
+            
+            if (record->drh.vib.vif & MBUS_DIB_VIF_EXTENSION_BIT)
             {
-                // VIFE
-                record->drh.vib.nvife = 0;
+                record->drh.vib.vife[0] = frame->data[i];
+                record->drh.vib.nvife++;
+                
                 while (frame->data[i] & MBUS_DIB_VIF_EXTENSION_BIT && 
                        record->drh.vib.nvife < NITEMS(record->drh.vib.vife))
                 {
@@ -2710,7 +2726,7 @@ mbus_data_variable_parse(mbus_frame *frame, mbus_data_variable *data)
                     record->drh.vib.nvife++;
                     i++;
                 }
-                i++;       
+                i++;
             }
                 
             // re-calculate data length, if of variable length type