diff --git a/docs/grub.texi b/docs/grub.texi
index cb5fe6e08..eeb3118eb 100644
--- a/docs/grub.texi
+++ b/docs/grub.texi
@@ -4305,7 +4305,8 @@ devices; option @option{-b} configures all geli containers that have boot flag s
 
 GRUB suports devices encrypted using LUKS, LUKS2 and geli. Note that necessary
 modules (@var{luks}, @var{luks2} and @var{geli}) have to be loaded manually
-before this command can be used.
+before this command can be used. For LUKS2 only the PBKDF2 key derivation
+function is supported, as Argon2 is not yet supported.
 @end deffn
 
 @node cutmem