moves to-/fromhost past the end of the RAM

env/iss/link.lds

@@ -178,7 +178,7 @@ SECTIONS
     PROVIDE( _sp = . );
   } >ram AT>ram :ram
 
-  PROVIDE( tohost = 0xfffffff0 );
-  PROVIDE( fromhost = 0xfffffff8 );
+  PROVIDE( tohost = . );
+  PROVIDE( fromhost = . + 8 );
 }