diff --git a/radio/src/opentx.cpp b/radio/src/opentx.cpp
index 02e7fcfca..0e6429cf0 100644
--- a/radio/src/opentx.cpp
+++ b/radio/src/opentx.cpp
@@ -303,7 +303,7 @@ void generalDefault()
 #endif
 
   for (uint8_t i=0; i<PXX2_LEN_REGISTRATION_ID; i++) {
-    g_eeGeneral.ownerRegistrationID[i] = (cpu_uid[1 + i] & 0x3f) - 32;
+    g_eeGeneral.ownerRegistrationID[i] = (cpu_uid[1 + i] & 0x3f) - 26;
   }
 
   g_eeGeneral.chkSum = 0xFFFF;
diff --git a/radio/src/opentx.h b/radio/src/opentx.h
index 1324a6ae0..673b0ab26 100644
--- a/radio/src/opentx.h
+++ b/radio/src/opentx.h
@@ -435,7 +435,7 @@ char zchar2char(int8_t idx);
 int8_t char2zchar(char c);
 void str2zchar(char *dest, const char *src, int size);
 int zchar2str(char *dest, const char *src, int size);
-int cmpStrWithZchar(char * charString, char * zcharString, int size);
+bool cmpStrWithZchar(const char * charString, const char * zcharString, int size);
 
 #include "keys.h"
 #include "pwr.h"
diff --git a/radio/src/strhelpers.cpp b/radio/src/strhelpers.cpp
index f7632ec11..e0e047376 100644
--- a/radio/src/strhelpers.cpp
+++ b/radio/src/strhelpers.cpp
@@ -52,7 +52,7 @@ int8_t char2zchar(char c)
 #endif
   if (c >= 'a') return 'a' - c - 1;
   if (c >= 'A') return c - 'A' + 1;
-  if (c >= '0') return -(c - '0' + 27);
+  if (c >= '0') return c - '0' + 27;
   if (c == '-') return 38;
   if (c == '.') return 39;
   if (c == ',') return 40;
@@ -78,14 +78,14 @@ int zchar2str(char * dest, const char * src, int size)
   return size+1;
 }
 
-int cmpStrWithZchar(char * charString, char * zcharString, int size)
+bool cmpStrWithZchar(const char * charString, const char * zcharString, int size)
 {
-  for(int i=0; i < size; i++) {
-    if((uint8_t)char2zchar(charString[i]) != (uint8_t)zcharString[i]) {
-      return 1;
+  for (int i=0; i<size; i++) {
+    if (char2zchar(charString[i]) != (int8_t)zcharString[i]) {
+      return false;
     }
   }
-  return 0;
+  return true;
 }
 
 unsigned int effectiveLen(const char * str, unsigned int size)
diff --git a/radio/src/telemetry/telemetry.cpp b/radio/src/telemetry/telemetry.cpp
index 5de62bb3e..002fad018 100644
--- a/radio/src/telemetry/telemetry.cpp
+++ b/radio/src/telemetry/telemetry.cpp
@@ -84,8 +84,8 @@ void processRegisterFrame(uint8_t module, uint8_t * frame)
   }
   else if (frame[3] == 0x01 && reusableBuffer.modelSetup.pxx2.registerStep == REGISTER_RX_NAME_SELECTED) {
     // RX_NAME + PASSWORD follow, we check they are good
-    if (cmpStrWithZchar((char *) &frame[4], reusableBuffer.modelSetup.pxx2.registerRxName, PXX2_LEN_RX_NAME) == 0 &&
-      cmpStrWithZchar((char *)&frame[12], g_model.modelRegistrationID, PXX2_LEN_REGISTRATION_ID) == 0) {
+    if (cmpStrWithZchar((char *)&frame[4], reusableBuffer.modelSetup.pxx2.registerRxName, PXX2_LEN_RX_NAME) &&
+      cmpStrWithZchar((char *)&frame[12], g_model.modelRegistrationID, PXX2_LEN_REGISTRATION_ID)) {
       reusableBuffer.modelSetup.pxx2.registerStep = REGISTER_OK;
       moduleSettings[module].mode = MODULE_MODE_NORMAL;
       POPUP_INFORMATION(STR_REG_OK);