Changing kernel in grub 2

[don fisher]

I have been using grub1, where you could edit the menu.1st command to 
change kernels. The only place that I see the kernels listed is in 
/boot/grub2/grub.cfg which is generated by the files in /etc.

If the current kernel does not work as desired, how does one choose the 
previous kernel? The only choices I see are:

1. edit the script that says do not edit
2. remove the bad kernel from /boot and run grub2-mkconfig

Please advise. Once boot is broken, it is really bad!

Thanks,
don