diff --git a/CHANGELOG.md b/CHANGELOG.md
index 83607321..68f6f0d6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,7 +7,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 
 ## [Unreleased]
 ### Added
-- Support for EEPROM
+- Support for mock EEPROM (but only if board supports it)
 
 ### Changed
 - Move repository from https://github.com/ianfixes/arduino_ci to https://github.com/Arduino-CI/arduino_ci
@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/).
 ### Removed
 
 ### Fixed
+- Don't define `ostream& operator<<(nullptr_t)` if already defined by Apple
 
 ### Security
 
diff --git a/SampleProjects/TestSomething/test/eeprom.cpp b/SampleProjects/TestSomething/test/eeprom.cpp
index ead3e371..440d6f1c 100644
--- a/SampleProjects/TestSomething/test/eeprom.cpp
+++ b/SampleProjects/TestSomething/test/eeprom.cpp
@@ -1,5 +1,8 @@
 #include <ArduinoUnitTests.h>
 #include <Arduino.h>
+
+// Only run EEPROM tests if there is hardware support!
+#if defined(EEPROM_SIZE) || (defined(E2END) && E2END)
 #include <EEPROM.h>
 
 unittest(length)
@@ -7,4 +10,6 @@ unittest(length)
   assertEqual(EEPROM_SIZE, EEPROM.length());
 }
 
+#endif
+
 unittest_main()
diff --git a/cpp/arduino/EEPROM.h b/cpp/arduino/EEPROM.h
index 75df36c6..39fa91f8 100644
--- a/cpp/arduino/EEPROM.h
+++ b/cpp/arduino/EEPROM.h
@@ -4,7 +4,7 @@
   New version by Christopher Andrews 2015.
 
   Copy of https://github.com/arduino/ArduinoCore-megaavr/blob/c8a1dd996c783777ec46167cfd8ad3fd2e6df185/libraries/EEPROM/src/EEPROM.h
-  modified by James Foster 2020 to work with Arduino CI.
+  modified by James Foster in 2020 to work with Arduino CI.
 
   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
@@ -27,13 +27,24 @@
 #include <inttypes.h>
 #include <avr/io.h>
 
-// I see EEPROM_SIZE defined in various arv/io*.h files; why isn't it defined here?
-#define EEPROM_SIZE (4096)
-// Is this all the custom code required?
+// different EEPROM implementations have different macros that leak out
+#if !defined(EEPROM_SIZE) && defined(E2END) && (E2END)
+#define EEPROM_SIZE (E2END + 1)
+#endif 
+
+// Does the current board have EEPROM?
+#ifndef EEPROM_SIZE
+// In lieu of an "EEPROM.h not found" error for unsupported boards
+#error "EEPROM library not available for your board"
+#endif
+
+// On a real device this would be in hardware, but we have a mock board!
 static uint8_t eeprom[EEPROM_SIZE];
 inline uint8_t eeprom_read_byte( uint8_t* index ) { return eeprom[(unsigned long) index % EEPROM_SIZE]; }
 inline void eeprom_write_byte( uint8_t* index, uint8_t value ) { eeprom[(unsigned long) index % EEPROM_SIZE] = value; }
 
+// Everything following is from the original (referenced above)
+
 /***
     EERef class.
     
@@ -152,4 +163,4 @@ struct EEPROMClass{
 };
 
 static EEPROMClass EEPROM;
-#endif
\ No newline at end of file
+#endif
diff --git a/cpp/unittest/OstreamHelpers.h b/cpp/unittest/OstreamHelpers.h
index a2cd8f45..14280d3a 100644
--- a/cpp/unittest/OstreamHelpers.h
+++ b/cpp/unittest/OstreamHelpers.h
@@ -2,4 +2,8 @@
 
 #include <ostream>
 
+#if (defined __apple_build_version__) && (__apple_build_version__ >= 12000000)
+// defined in /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/ostream:223:20
+#else
 inline std::ostream& operator << (std::ostream& out, const std::nullptr_t &np) { return out << "nullptr"; }
+#endif