[HOW TO] set an older kernel to default boot

@Aravisian I know this Tutorial has been heavily relied upon over time, but particularly recently.
It may be good if the Tutorial was checked over and verified, as I have seen two posts today where users have used it but the 7.0 kernel was booted instead of the older 6.17 one. I will try and link the 2 posts if I can find them again. Zab.

EDIT: Found them:-