diff --git a/js/xpconnect/loader/moz.build b/js/xpconnect/loader/moz.build
index 38fa13e1275d..af7d6b10a8d7 100644
--- a/js/xpconnect/loader/moz.build
+++ b/js/xpconnect/loader/moz.build
@@ -4,8 +4,6 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
-# These files cannot be built in unified mode because they rely on plarena.h
-# and they want to force NSPR logging.
 SOURCES += [
     'mozJSComponentLoader.cpp',
     'mozJSLoaderUtils.cpp',
diff --git a/js/xpconnect/src/moz.build b/js/xpconnect/src/moz.build
index 5010b64aea69..00bd09627038 100644
--- a/js/xpconnect/src/moz.build
+++ b/js/xpconnect/src/moz.build
@@ -13,12 +13,13 @@ EXPORTS += [
     'xpcpublic.h',
 ]
 
-UNIFIED_SOURCES += [
+SOURCES += [
     'nsCxPusher.cpp',
     'nsScriptError.cpp',
     'nsXPConnect.cpp',
     'Sandbox.cpp',
     'XPCCallContext.cpp',
+    'XPCComponents.cpp',
     'XPCContext.cpp',
     'XPCConvert.cpp',
     'XPCDebug.cpp',
@@ -47,11 +48,6 @@ UNIFIED_SOURCES += [
     'XPCWrapper.cpp',
 ]
 
-# XPCComponents.cpp cannot be built in unified mode because it uses plarena.h.
-SOURCES += [
-    'XPCComponents.cpp',
-]
-
 GENERATED_SOURCES += [
     'DictionaryHelpers.cpp',
     'dom_quickstubs.cpp',
diff --git a/js/xpconnect/tests/components/native/moz.build b/js/xpconnect/tests/components/native/moz.build
index bb6c4e8040de..a1d17d666102 100644
--- a/js/xpconnect/tests/components/native/moz.build
+++ b/js/xpconnect/tests/components/native/moz.build
@@ -6,7 +6,7 @@
 
 NO_DIST_INSTALL = True
 
-UNIFIED_SOURCES += [
+SOURCES += [
     'xpctest_attributes.cpp',
     'xpctest_module.cpp',
     'xpctest_params.cpp',
diff --git a/js/xpconnect/wrappers/moz.build b/js/xpconnect/wrappers/moz.build
index 0166a091f40c..a12a03ef6f97 100644
--- a/js/xpconnect/wrappers/moz.build
+++ b/js/xpconnect/wrappers/moz.build
@@ -8,16 +8,12 @@ EXPORTS += [
     'WrapperFactory.h',
 ]
 
-UNIFIED_SOURCES += [
+SOURCES += [
     'AccessCheck.cpp',
     'ChromeObjectWrapper.cpp',
     'FilteringWrapper.cpp',
     'WaiveXrayWrapper.cpp',
     'WrapperFactory.cpp',
-]
-
-# XrayWrapper needs to be built separately becaue of template instantiations.
-SOURCES += [
     'XrayWrapper.cpp',
 ]