diff --git a/gnu/system/image.scm b/gnu/system/image.scm
index a83f844682..a6267feab2 100644
--- a/gnu/system/image.scm
+++ b/gnu/system/image.scm
@@ -317,10 +317,15 @@ (define (partition->dos-type partition)
     (define (partition->gpt-type partition)
       ;; Return the genimage GPT partition type code corresponding to PARTITION.
       ;; See https://github.com/pengutronix/genimage/blob/master/README.rst
-      (let ((flags (partition-flags partition)))
+      (let ((flags (partition-flags partition)) (file-system (partition-file-system partition)))
         (cond
           ((member 'esp flags) "U")
-          (else "L"))))
+          ((string-prefix? "ext" file-system) "L")
+          ((string=? file-system "vfat") "F")
+          (else
+            (raise (condition
+              (&message
+               (message "unsupported partition type"))))))))
 
     (define (partition-image partition)
       ;; Return as a file-like object, an image of the given PARTITION.  A