diff --git a/modules/freya/bootloader/uki.scm b/modules/freya/bootloader/uki.scm
index f62af45..716e8a2 100644
--- a/modules/freya/bootloader/uki.scm
+++ b/modules/freya/bootloader/uki.scm
@@ -44,14 +44,12 @@
                          (ice-9 popen) (ice-9 textual-ports))
 
             (define (out name) (string-append vendir "/" name))
-            (define fulldisk
+            (define disk
               (call-with-port
                 (open-pipe* OPEN_READ findmnt "-fnro" "SOURCE" "-T" target)
                 (lambda (port) (get-line port)))) ; only 1 line: the device
-            (define disk
-              (substring fulldisk 0 (- (string-length fulldisk) 1)))
             (define part
-              (substring fulldisk (- (string-length fulldisk) 1)))
+              (substring disk (- (string-length disk) 1)))
 
             ;; delete all boot entries and files we control
             (when (file-exists? schema)