Make sure we don't use any upper-memory stack during shuffle

We want to make sure everything stays below 7C00h during the
shuffle_and_boot operation.
diff --git a/ b/
index c1c850c..afb458e 100644
--- a/
+++ b/
@@ -153,6 +153,10 @@
 		pop bx			; Copy from...
 		pop ax			; Copy list count
+		; Make extra sure we don't continue to use any stack
+		; in high memory.
+		mov dword [PMESP],StackTop
 		mov cx,es
 		mov ss,cx