diff --git a/ext/etc/etc.c b/ext/etc/etc.c
index 8d50a96..627dc92 100644
--- a/ext/etc/etc.c
+++ b/ext/etc/etc.c
@@ -813,18 +813,7 @@ etc_uname(VALUE obj)
         rb_sys_fail("GetVersionEx");
 
     result = rb_hash_new();
-    switch (v.dwPlatformId) {
-      case VER_PLATFORM_WIN32s:
-	sysname = "Win32s";
-	break;
-      case VER_PLATFORM_WIN32_NT:
-	sysname = "Windows_NT";
-	break;
-      case VER_PLATFORM_WIN32_WINDOWS:
-      default:
-	sysname = "Windows";
-	break;
-    }
+    sysname = "Windows_NT";
     rb_hash_aset(result, SYMBOL_LIT("sysname"), rb_str_new_cstr(sysname));
     release = rb_sprintf("%lu.%lu.%lu", v.dwMajorVersion, v.dwMinorVersion, v.dwBuildNumber);
     rb_hash_aset(result, SYMBOL_LIT("release"), release);
@@ -847,6 +836,9 @@ etc_uname(VALUE obj)
 # endif
 # ifndef PROCESSOR_ARCHITECTURE_INTEL
 #   define PROCESSOR_ARCHITECTURE_INTEL 0
+# endif
+# ifndef PROCESSOR_ARCHITECTURE_ARM64
+#   define PROCESSOR_ARCHITECTURE_ARM64 12
 # endif
     GetSystemInfo(&s);
     switch (s.wProcessorArchitecture) {
@@ -856,6 +848,9 @@ etc_uname(VALUE obj)
       case PROCESSOR_ARCHITECTURE_ARM:
 	mach = "ARM";
 	break;
+      case PROCESSOR_ARCHITECTURE_ARM64:
+	mach = "ARM64";
+	break;
       case PROCESSOR_ARCHITECTURE_INTEL:
 	mach = "x86";
 	break;