diff --git a/src/mudsys/initm.374 b/src/mudsys/initm.374
index 6e501009..6eb9c86b 100644
--- a/src/mudsys/initm.374
+++ b/src/mudsys/initm.374
@@ -462,10 +462,16 @@ PURIMP:	MOVE	A,FRETOP
 	HRL	B,A
 	DOTCAL	CORBLK,[[1000,,0],[1000,,-1],B]
 	 FATAL	INITM -- CAN'T FLUSH MIDDLE CORE
-;Disabled because this fails with ITS 1648.
-;	MOVE	A,[-<400-PHIBOT>,,PHIBOT]
-;	DOTCAL	CORBLK,[[1000,,210000],[1000,,-1],A]
-;	 FATAL	INITM -- CAN'T PURIFY HIGH CORE
+	MOVE	B,RHITOP
+	SUBI	B,1
+	ASH	B,-10.
+	MOVEI	A,PHIBOT
+	SUB	A,B
+	SUBI	A,1
+	HRLS	A
+	HRRI	A,PHIBOT
+	DOTCAL	CORBLK,[[1000,,210000],[1000,,-1],A]
+	 FATAL	INITM -- CAN'T PURIFY HIGH CORE
 ]
 
 IFE ITS,[