diff --git a/src/pyj/read_book/annotations.pyj b/src/pyj/read_book/annotations.pyj
index 15e49acdfb..cb7718d55e 100644
--- a/src/pyj/read_book/annotations.pyj
+++ b/src/pyj/read_book/annotations.pyj
@@ -18,7 +18,8 @@ def bookmark_get_cfi(b):
 def highlight_get_cfi(hl):
     cfi = hl.start_cfi
     if cfi:
-        return cfi[8:-1]
+        si = hl.spine_index or 9999999999
+        return f'/{si}/{cfi}'
 
 
 def sort_annot_list(annots, get_cfi_func):