diff --git a/C/grow.c b/C/grow.c
index 63f79bda8..180bf6eae 100644
--- a/C/grow.c
+++ b/C/grow.c
@@ -120,8 +120,10 @@ SetHeapRegs(void)
   Yap_TrailTop = TrailAddrAdjust(Yap_TrailTop);
   Yap_GlobalBase = DelayAddrAdjust(Yap_GlobalBase);
   Yap_LocalBase = LocalAddrAdjust(Yap_LocalBase);
+#if !USE_SYSTEM_MALLOC
   AuxSp = PtoDelayAdjust(AuxSp);
   AuxTop = (ADDR)PtoDelayAdjust((CELL *)AuxTop);
+#endif
   HeapLim = DelayAddrAdjust(HeapLim);
   /* The registers pointing to one of the stacks */
   ENV = PtoLocAdjust(ENV);
diff --git a/pl/boot.yap b/pl/boot.yap
index f88182ba9..94986128e 100644
--- a/pl/boot.yap
+++ b/pl/boot.yap
@@ -848,7 +848,6 @@ break :- get_value('$break',BL), NBL is BL+1,
         '$consult'(X),
         '$change_module'(M0).
 '$consult'(X) :-
-	'$lock_system',
 	'$find_in_path'(X,Y,consult(X)),
 	'$open'(Y,'$csult',Stream,0), !,
 	'$current_module'(OldModule),
@@ -875,7 +874,6 @@ break :- get_value('$break',BL), NBL is BL+1,
 	get_value('$consulting',Old),
 	set_value('$consulting',true),
 	recorda('$initialisation','$',_),
-	'$unlock_system',
 	( '$undefined'('$print_message'(_,_),prolog) -> 
 	    ( get_value('$verbose',on) ->
 		'$format'(user_error, "~*|[ consulting ~w... ]~n", [LC,F])