doc: added steps for updating kernel manually in AWS installation

README.md

@@ -203,7 +203,18 @@ lsmod | grep snd_aloop
 ```
 
 NOTE: if you are running on AWS you may need to reboot your machine to use the generic kernel instead
-of the "aws" kernel.
+of the "aws" kernel. If after reboot, your machine is still using the "aws" kernel, you'll need to manually update the grub file. So just run
+```
+# open the grub file in editor
+nano /etc/default/grub
+# Modify the value of GRUB_DEFAULT from "0" to "1>2"
+# Save and exit from file
+
+# Update grub
+update-grub
+# Reboot the machine
+reboot now
+```
 
 If you want to enable Jibri these options are required: