diff --git a/src/toolkit/mozapps/update/updater/updater-cpp.patch b/src/toolkit/mozapps/update/updater/updater-cpp.patch
deleted file mode 100644
index a2dcb66d2..000000000
--- a/src/toolkit/mozapps/update/updater/updater-cpp.patch
+++ /dev/null
@@ -1,45 +0,0 @@
-diff --git a/toolkit/mozapps/update/updater/updater.cpp b/toolkit/mozapps/update/updater/updater.cpp
-index 5042328c0ee521300a6897b21849abf8dcbd9d45..a7898bcf5f2a15119b8c5cf9ae71f2a1a749e56d 100644
---- a/toolkit/mozapps/update/updater/updater.cpp
-+++ b/toolkit/mozapps/update/updater/updater.cpp
-@@ -2436,15 +2436,37 @@ bool LaunchWinPostProcess(const WCHAR* installationDir,
-   // N.b.: two null terminating characters!  The first terminates a non-existent
-   // key-value pair, the second (automatically added) terminates the block of
-   // key-value pairs.
--  const WCHAR* emptyEnvironment = L"\0";
-+  // %SystemRoot% must be preserved, however.  Without it the NSIS post-update
-+  // helper cannot load its plugin DLLs, so
-+  // ServicesHelper::PathToUniqueRegistryPath returns an empty string and
-+  // AddMaintCertKeys silently does nothing.  That leaves the maintenance
-+  // service's allowed-certificate registry keys stale forever, which means a
-+  // code signing certificate rotation can never complete through updates.
-+  const WCHAR* environment = L"\0";
-+  WCHAR environmentBlock[MAX_PATH + 16] = {L'\0'};
-+  WCHAR systemRoot[MAX_PATH + 1] = {L'\0'};
-+  DWORD systemRootLen =
-+      GetEnvironmentVariableW(L"SystemRoot", systemRoot, MAX_PATH + 1);
-+  if (systemRootLen > 0 && systemRootLen <= MAX_PATH) {
-+    // environmentBlock is zero initialized and oversized relative to
-+    // "SystemRoot=" plus a MAX_PATH value, so the second terminating null
-+    // character is already present after the string's own terminator.
-+    wcsncpy(environmentBlock, L"SystemRoot=",
-+            sizeof(environmentBlock) / sizeof(environmentBlock[0]) - 1);
-+    wcscat(environmentBlock, systemRoot);
-+    environment = environmentBlock;
-+  } else {
-+    LOG(("LaunchWinPostProcess could not read SystemRoot; the post update "
-+         "process will not be able to load its plugins"));
-+  }
- 
-   bool ok =
-       CreateProcessW(exefullpath, cmdline,
-                      nullptr,  // no special security attributes
-                      nullptr,  // no special thread attributes
-                      false,    // don't inherit filehandles
--                     0,        // No special process creation flags
--                     (LPVOID)emptyEnvironment, workingDirectory, &si, &pi);
-+                     CREATE_UNICODE_ENVIRONMENT, (LPVOID)environment,
-+                     workingDirectory, &si, &pi);
-   free(cmdline);
-   if (ok) {
-     LOG(("LaunchWinPostProcess - Waiting for process to complete"));