diff --git a/libc/tzcode/bionic.cpp b/libc/tzcode/bionic.cpp
index 1742d7941..6d84303a4 100644
--- a/libc/tzcode/bionic.cpp
+++ b/libc/tzcode/bionic.cpp
@@ -199,37 +199,36 @@ static int __bionic_open_tzdata_path(const char* path,
 int __bionic_open_tzdata(const char* olson_id, int32_t* entry_length) {
   int fd;
 
-#if defined(__ANDROID__)
-  // On Android devices, try the four hard-coded locations in order.
-  //
+  // Try the three locations for the tzdata file in a strict order:
   // 1: The O-MR1 time zone updates via APK update mechanism. This is
-  // tried first because it allows us to test that the time zone updates
-  // via APK mechanism still works even on devices with the time zone
-  // module.
+  //    tried first because it allows us to test that the time zone updates
+  //    via APK mechanism still works even on devices with the time zone
+  //    module.
+  // 2: The time zone data module which contains the main copy. This is the
+  //    common case.
+  // 3: The ultimate fallback: the non-updatable copy in /system.
+
+#if defined(__ANDROID__)
+  // On Android devices, bionic has to work even if exec takes place without
+  // environment variables set. So, all paths are hardcoded here.
+
   fd = __bionic_open_tzdata_path("/data/misc/zoneinfo/current/tzdata",
                                  olson_id, entry_length);
   if (fd >= 0) return fd;
 
-  // 2: The time zone data module which may contain newer data on
-  // devices that support module updates.
   fd = __bionic_open_tzdata_path("/apex/com.android.tzdata/etc/tz/tzdata",
                                  olson_id, entry_length);
   if (fd >= 0) return fd;
 
-  // 3: The runtime module, which should exist even on devices that
-  // do not support APEX file updates.
-  fd = __bionic_open_tzdata_path("/apex/com.android.runtime/etc/tz/tzdata",
-                                 olson_id, entry_length);
-  if (fd >= 0) return fd;
-
-  // 4: The ultimate fallback: the non-updatable copy in /system.
   fd = __bionic_open_tzdata_path("/system/usr/share/zoneinfo/tzdata",
                                  olson_id, entry_length);
   if (fd >= 0) return fd;
 #else
-  // On the host, we don't expect those locations to exist, and we're not
-  // worried about security so we trust $ANDROID_DATA, $ANDROID_RUNTIME_ROOT,
-  // $ANDROID_TZDATA_ROOT, and $ANDROID_ROOT to point us in the right direction.
+  // On the host, we don't expect the hard-coded locations above to exist, and
+  // we're not worried about security so we trust $ANDROID_DATA,
+  // $ANDROID_TZDATA_ROOT, and $ANDROID_ROOT to point us in the right direction
+  // instead.
+
   char* path = make_path("ANDROID_DATA", "/misc/zoneinfo/current/tzdata");
   fd = __bionic_open_tzdata_path(path, olson_id, entry_length);
   free(path);
@@ -240,11 +239,6 @@ int __bionic_open_tzdata(const char* olson_id, int32_t* entry_length) {
   free(path);
   if (fd >= 0) return fd;
 
-  path = make_path("ANDROID_RUNTIME_ROOT", "/etc/tz/tzdata");
-  fd = __bionic_open_tzdata_path(path, olson_id, entry_length);
-  free(path);
-  if (fd >= 0) return fd;
-
   path = make_path("ANDROID_ROOT", "/usr/share/zoneinfo/tzdata");
   fd = __bionic_open_tzdata_path(path, olson_id, entry_length);
   free(path);