diff -ru rebuilt/u2.s build/u2.s
--- rebuilt/u2.s	2008-05-04 15:29:30.000000000 -1000
+++ build/u2.s	2008-05-04 15:45:52.000000000 -1000
@@ -177,6 +177,33 @@
 			     / number of words less 26 available for
 			     / program in user core
 	mov	r5,u.count /
+
+	/ 0407 binary support added may 2008.
+	br	1f
+bsz:	0	/ XXX is there a reg that I can use over a call to readi?
+1:
+	cmp	core,$407
+	bne	e407
+	add	$4,u.off / skip last two header words
+	mov	$core,r4
+	mov	r4,u.base / continue reading at core.
+	mov	core+2,r5
+	add	core+4,r5 / r5 = text+data size
+	mov	core+6,bsz / save bss size, we're going to overwrite core
+	/ XXX fix me, I dont quite understand what to do here or
+	/ what is done in the similar code below e407:
+	/ cmp	r5, u.count / see if theres enough room
+	/ bgt	1f
+	mov	r5,u.count / read text+data into core
+	jsr	r0,readi
+	mov	u.nread,u.break / break = core + nread + bss
+	add	$core,u.break
+	add	bsz,u.break
+	jsr	r0,iclose
+	br	sysret3
+e407:
+	/ end 0407 support
+
 	cmp	core,$405 / br .+14 is first instruction if file is
 			  / standard a.out format
 	bne	1f / branch, if not standard format