Index: launch.scm
==================================================================
--- launch.scm
+++ launch.scm
@@ -593,11 +593,11 @@
 		    (configf:write-alist *configdat* tmpfile)
 		    (system (conc "ln -sf " tmpfile " " targfile))
 		    )))))))
 
 (define (get-best-disk confdat testconfig)
-  (let* ((disks   (or (hash-table-ref/default confdat "disks" #f)
+  (let* ((disks   (or (and testconfig (hash-table-ref/default testconfig "disks" #f))
 		      (hash-table-ref/default confdat "disks" #f)))
 	 (minspace (let ((m (configf:lookup confdat "setup" "minspace")))
 		     (string->number (or m "10000")))))
     (if disks 
 	(let ((res (common:get-disk-with-most-free-space disks minspace))) ;; min size of 1000, seems tad dumb