diff --git a/lisp/hppa-assem.S b/lisp/hppa-assem.S
index bc753725c8dcbb7a87a13cbdf4dd45baedf3d5ad..1bba23e0c2dd2e7c3f82c7550416fe27850c433b 100644
--- a/lisp/hppa-assem.S
+++ b/lisp/hppa-assem.S
@@ -308,9 +308,8 @@ undefined_tramp
         .byte	UNDEFINED_SYMBOL_ERROR
         /* Escape to create 16bit BE number from following two values */
         .byte	254
-        /* SC_OFFSET(sc_DescriptorReg,reg_LEXENV) */
-	/* Shouldn't this be reg_FDEFN, instead? */
-        .byte	(0x40 + sc_DescriptorReg)
+        /* SC_OFFSET(sc_DescriptorReg,reg_FDEFN) */
+        .byte	(0x20 + sc_DescriptorReg)
         .byte	1
 	.align	4