diff --git a/src/arch/x86/isa/insts/romutil.py b/src/arch/x86/isa/insts/romutil.py
index beeda3d12c..e47259eb3b 100644
--- a/src/arch/x86/isa/insts/romutil.py
+++ b/src/arch/x86/isa/insts/romutil.py
@@ -99,7 +99,7 @@ def rom
     br rom_local_label("%(startLabel)s_stackSwitched")
 
 %(startLabel)s_istStackSwitch:
-    panic "IST based stack switching isn't implemented"
+    ld t6, tr, [8, t12, t0], 0x1c, dataSize=8, addressSize=8, atCPL0=True
     br rom_local_label("%(startLabel)s_stackSwitched")
 
 %(startLabel)s_cplStackSwitch: