diff --git a/DuetPkg/BootSector/st32_64.S b/DuetPkg/BootSector/st32_64.S
index 465b1cf9b2..18c53f81fa 100644
--- a/DuetPkg/BootSector/st32_64.S
+++ b/DuetPkg/BootSector/st32_64.S
@@ -601,7 +601,7 @@ Empty8042Loop:
 
         .p2align 1
 
-        gdtr:    .long  GDT_END - GDT_BASE - 1  # GDT limit 
+        gdtr:    .word  GDT_END - GDT_BASE - 1  # GDT limit 
         .long 0                     # (GDT base gets set above)
 ##############################################################################
 #   global descriptor table (GDT)