diff --git a/core/core-modeline.el b/core/core-modeline.el
index 59c4334ff..04600475e 100644
--- a/core/core-modeline.el
+++ b/core/core-modeline.el
@@ -217,8 +217,12 @@ directory, the file name, and its state (modified, read-only or non-existent)."
             (cond ((eq eol-type 0) "LF  ")
                   ((eq eol-type 1) "CRLF  ")
                   ((eq eol-type 2) "CR  ")))
-          (let ((coding-sys (plist-get (coding-system-plist buffer-file-coding-system) :name)))
-            (upcase (symbol-name (if (eq coding-sys 'prefer-utf-8) 'utf-8 coding-sys))))
+          (let* ((sys (coding-system-plist buffer-file-coding-system))
+                 (sys-name (plist-get sys :name))
+                 (sys-cat (plist-get sys :category)))
+            (cond ((memq sys-cat '(coding-category-undecided coding-category-utf-8))
+                   "UTF-8")
+                  (t (upcase (symbol-name sys-name)))))
           "  "))
 
 (defun *major-mode ()