diff --git a/sbus-to-ztex/prom.forth b/sbus-to-ztex/prom.forth
index 27152c3..40d0871 100644
--- a/sbus-to-ztex/prom.forth
+++ b/sbus-to-ztex/prom.forth
@@ -1,16 +1,33 @@
-\ version1 fcode-revision
-fcode-version1
-
-\ beware the space with the quotes, Forth is strict
-\ minimal required stuff
-\ " RDOL,SBusFPGA" encode-string " name" property
-\ my-address h# 200 + my-space encode-phys
-\ h# 100 encode-int encode+
-\ " reg" property
+fcode-version2
 
+\ Absolute minimal stuff; name & registers def.
 " RDOL,SBusFPGA" name
 my-address h# 200 + my-space h# 100 reg
+\ we don't support ET
+h# 7f xdrint " slave-burst-sizes" attribute
 
+headers
+
+-1 instance value led-virt
+my-address constant my-sbus-address
+my-space   constant my-sbus-space
+
+: map-in ( adr space size -- virt ) " map-in" $call-parent ;
+: map-out ( virt size -- ) " map-out" $call-parent ;
+
+: map-in-led ( -- ) my-sbus-address h# 200 + my-sbus-space h# 4 map-in is led-virt ;
+: map-out-led ( -- ) led-virt h# 4 map-out ;
+
+external
+
+: blink! ( pattern -- )
+	map-in-led
+	led-virt l! ( pattern virt -- )
+	map-out-led
+	;
+
+\ works at probe time, but not as a user command
+h# 12488421 blink!
 
 \ \hex