diff --git a/mach/mantra/libsys/head_em.s b/mach/mantra/libsys/head_em.s
index b878d6491..5d7611c82 100644
--- a/mach/mantra/libsys/head_em.s
+++ b/mach/mantra/libsys/head_em.s
@@ -1,5 +1,5 @@
 .define .lino,.filn
-.define EXIT
+.define EXIT,WRITE,BRK
 .define	begtext,begdata,begbss
 .define	EARRAY,ERANGE,ESET,EIDIVZ,EHEAP,EILLINS,ECASE,EBADGTO
 .define	hol0,.reghp,.limhp,.trpim,.trppc
@@ -56,6 +56,10 @@ EXIT:
 	move.l	d0,-(sp)
 	jsr	__exit
 
+WRITE:	jmp	__write
+
+BRK:	jmp	__brk
+
 	.sect .data
 begdata:
 hol0:
diff --git a/mach/pmds4/libsys/head_em.s b/mach/pmds4/libsys/head_em.s
index 4bed638db..b0c14d862 100644
--- a/mach/pmds4/libsys/head_em.s
+++ b/mach/pmds4/libsys/head_em.s
@@ -1,6 +1,6 @@
 .define	CERASE,CKILL,CSTOP,CSTART
 .define .lino,.filn
-.define F_DUM,EXIT
+.define F_DUM,EXIT,WRITE,BRK
 .define	begtext,begdata,begbss
 .define	EARRAY,ERANGE,ESET,EIDIVZ,EHEAP,EILLINS,ECASE
 .define	hol0,.reghp,.limhp,.trpim,.trppc
@@ -43,6 +43,9 @@ EXIT:
 	! As a temporary measure
 	jsr .trp
 	
+WRITE:	jmp	__write
+
+BRK:	jmp	__brk
 
 	.sect .data
 begdata:
diff --git a/mach/sun2/libsys/head_em.s b/mach/sun2/libsys/head_em.s
index e0f8a3892..03553dc85 100644
--- a/mach/sun2/libsys/head_em.s
+++ b/mach/sun2/libsys/head_em.s
@@ -1,5 +1,5 @@
 .define .lino,.filn
-.define EXIT
+.define EXIT,WRITE,BRK
 .define	begtext,begdata,begbss
 .define	EARRAY,ERANGE,ESET,EIDIVZ,EHEAP,EILLINS,ECASE,EBADGTO
 .define	hol0,.reghp,.limhp,.trpim,.trppc
@@ -43,6 +43,10 @@ begtext:
 EXIT:
 	jsr	__exit
 
+WRITE:	jmp	__write
+
+BRK:	jmp	__brk
+
 	.sect .data
 begdata:
 	.data4 0		! may be at virtual address 0 with no problem