diff --git a/x86_64/startup-x86_64.asm b/x86_64/startup-x86_64.asm
index 95c01e2dc2..f5f9bc6a7d 100644
--- a/x86_64/startup-x86_64.asm
+++ b/x86_64/startup-x86_64.asm
@@ -58,8 +58,9 @@ startup_arch:
     rep stosd
 
     xor edi, edi
-    ;Link first PML4 to PDP
+    ;Link first PML4 and third to last PML4 to PDP
     mov DWORD [es:edi], 0x71000 | 1 << 1 | 1
+    mov DWORD [es:edi + 509*8], 0x71000 | 1 << 1 | 1
     add edi, 0x1000
     ;Link last PML4 to PML4
     mov DWORD [es:edi - 8], 0x70000 | 1 << 1 | 1