diff --git a/Enable-802.11mc-FTM-on-Intel-8260.md b/Enable-802.11mc-FTM-on-Intel-8260.md
index 5b96ee6..24fa16b 100644
--- a/Enable-802.11mc-FTM-on-Intel-8260.md
+++ b/Enable-802.11mc-FTM-on-Intel-8260.md
@@ -19,9 +19,10 @@ $ sudo wget https://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/linux-firmwa
 ### disable Ubuntu 16.04 kernel 4.4+ security check, this will reduce security of your system
 $ sudo apt install mokutil
 $ sudo mokutil --disable-validation
-$ reboot
 ```
 
+NOTE: make sure your kernel is using 4.13 not 4.15 (if updated, use advanced config on boot and boot via old kernel). Also, make sure you have `iwlwifi-8000C-31.ucode` in `/lib/firmware` after above command, and remove all `iwlwifi-8000C-*.ucode` where `* > 31`.
+
 ### Install
 ```
 $ git clone https://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/backport-iwlwifi.git -b release/LinuxCore30