diff --git a/book/arch/05-install-arch.md b/book/arch/05-install-arch.md
index f935b60..9f561d4 100644
--- a/book/arch/05-install-arch.md
+++ b/book/arch/05-install-arch.md
@@ -180,7 +180,7 @@ It should look something like this
 YKFDE_CHALLENGE="8fa0acf6233b92d2d48a30a315cd213748d48f28eaa63d7590509392316b3016"
 
 # Use 'Manual mode with secret challenge (2FA)'.
-#YKFDE_CHALLENGE_PASSWORD_NEEDED="1"
+YKFDE_CHALLENGE_PASSWORD_NEEDED="1"
 
 # YubiKey slot configured for 'HMAC-SHA1 Challenge-Response' mode.
 # Possible values are "1" or "2". Defaults to "2".
@@ -231,4 +231,4 @@ Good luck! Don't worry if something doesn't work, simply boot from the Arch Linu
 to mount your encrypted partitions and check the configs. Maybe an UUID is wrong.
 
 Now you can setup your Arch Linux e.g. create own user or add additional stuff [en](https://wiki.archlinux.org/index.php/installation_guide) / [de](https://wiki.archlinux.de/title/Anleitung_f%C3%BCr_Einsteiger).
-The next chapter describes how to setup UEFI secure boot. The last piece to bullet proof your full disk encryption.
\ No newline at end of file
+The next chapter describes how to setup UEFI secure boot. The last piece to bullet proof your full disk encryption.