diff --git a/tests/Makefile b/tests/Makefile
index 917286623b7..2f7cb8bf75a 100644
--- a/tests/Makefile
+++ b/tests/Makefile
@@ -85,9 +85,9 @@ test.config: Makefile $(TOP)/Make.config $(TOP)/mk/mono.mk $(TOP)/eng/Version.De
 	@printf "$(foreach platform,$(DOTNET_PLATFORMS_UPPERCASE),$(platform)_NUGET_REF_NAME=$($(platform)_NUGET_REF_NAME)\\n)" | sed 's/^ //' >> $@
 	@printf "$(foreach platform,$(DOTNET_PLATFORMS_UPPERCASE),$(foreach rid,$(DOTNET_$(platform)_RUNTIME_IDENTIFIERS),$(rid)_NUGET_RUNTIME_NAME=$($(rid)_NUGET_RUNTIME_NAME)\\n))" | sed 's/^ //' >> $@
 	@printf "$(foreach platform,$(DOTNET_PLATFORMS_UPPERCASE),SUPPORTED_API_VERSIONS_$(platform)='$(SUPPORTED_API_VERSIONS_$(platform))'\\n)" | sed 's/^ //' >> $@
-	@printf "ENABLE_XAMARIN=$(ENABLE_XAMARIN)" >> $@
-	@printf "XCODE_IS_STABLE=$(XCODE_IS_STABLE)" >> $@
-	@printf "XCODE_VERSION=$(XCODE_VERSION)" >> $@
+	@printf "ENABLE_XAMARIN=$(ENABLE_XAMARIN)\n" >> $@
+	@printf "XCODE_IS_STABLE=$(XCODE_IS_STABLE)\n" >> $@
+	@printf "XCODE_VERSION=$(XCODE_VERSION)\n" >> $@
 
 test-system.config: Makefile $(TOP)/Make.config $(TOP)/mk/mono.mk $(TOP)/eng/Version.Details.xml
 	@rm -f $@
@@ -119,9 +119,9 @@ test-system.config: Makefile $(TOP)/Make.config $(TOP)/mk/mono.mk $(TOP)/eng/Ver
 	@printf "$(foreach platform,$(DOTNET_PLATFORMS_UPPERCASE),$(platform)_NUGET_REF_NAME=$($(platform)_NUGET_REF_NAME)\\n)" | sed 's/^ //' >> $@
 	@printf "$(foreach platform,$(DOTNET_PLATFORMS_UPPERCASE),$(foreach rid,$(DOTNET_$(platform)_RUNTIME_IDENTIFIERS),$(rid)_NUGET_RUNTIME_NAME=$($(rid)_NUGET_RUNTIME_NAME)\\n))" | sed 's/^ //' >> $@
 	@printf "$(foreach platform,$(DOTNET_PLATFORMS_UPPERCASE),SUPPORTED_API_VERSIONS_$(platform)='$(SUPPORTED_API_VERSIONS_$(platform))'\\n)" | sed 's/^ //' >> $@
-	@printf "ENABLE_XAMARIN=$(ENABLE_XAMARIN)" >> $@
-	@printf "XCODE_IS_STABLE=$(XCODE_IS_STABLE)" >> $@
-	@printf "XCODE_VERSION=$(XCODE_VERSION)" >> $@
+	@printf "ENABLE_XAMARIN=$(ENABLE_XAMARIN)\n" >> $@
+	@printf "XCODE_IS_STABLE=$(XCODE_IS_STABLE)\n" >> $@
+	@printf "XCODE_VERSION=$(XCODE_VERSION)\n" >> $@
 
 clean-local::
 	$(Q) $(SYSTEM_XBUILD) /t:Clean /p:Platform=iPhoneSimulator /p:Configuration=$(CONFIG) $(XBUILD_VERBOSITY) tests.sln
diff --git a/tests/generator/BGenTool.cs b/tests/generator/BGenTool.cs
index 68c3faafe80..4326c98f24b 100644
--- a/tests/generator/BGenTool.cs
+++ b/tests/generator/BGenTool.cs
@@ -247,7 +247,7 @@ public static void AddPreviewNoWarn (IList<string> argumentList)
 		public static string? GetPreviewNoWarn (string? existingNowarn)
 		{
 			if (Configuration.XcodeIsStable)
-				return null;
+				return existingNowarn;
 
 			var previewNoWarn = $"XCODE_{Configuration.XcodeVersion.Major}_{Configuration.XcodeVersion.Minor}_PREVIEW";
 			if (string.IsNullOrEmpty (existingNowarn)) {