diff --git a/platformio.ini b/platformio.ini
index de4d6c29c..f296f8382 100644
--- a/platformio.ini
+++ b/platformio.ini
@@ -110,7 +110,9 @@ build_flags = ${arduino_base.build_flags}
 
 [stm32_base]
 extends = arduino_base
-platform = ststm32
+; Pinned pending upstream fix for upstream conversions.
+; https://github.com/jgromes/RadioLib/issues/1873
+platform = ststm32@19.7.1
 extra_scripts = post:arch/stm32/build_hex.py
 build_flags = ${arduino_base.build_flags}
   -D STM32_PLATFORM
diff --git a/src/helpers/TxtDataHelpers.cpp b/src/helpers/TxtDataHelpers.cpp
index d327931fd..4358c8b83 100644
--- a/src/helpers/TxtDataHelpers.cpp
+++ b/src/helpers/TxtDataHelpers.cpp
@@ -27,8 +27,13 @@ bool StrHelper::isBlank(const char* str) {
 }
 
 #include <Arduino.h>
+#include <stdio.h>
+#if __has_include(<api/itoa.h>)
+// https://github.com/stm32duino/Arduino_Core_STM32/issues/3084
+#include <api/itoa.h>
+#endif
 
-union int32_Float_t 
+union int32_Float_t
 {
   int32_t Long;
   float Float;
@@ -100,7 +105,7 @@ static void _ftoa(float f, char *p, int *status)
       *p++ = '-';
   if (int_part == 0)
     *p++ = '0';
-  else 
+  else
   {
     ltoa(int_part, p, 10);
     while (*p)