[Arm-dev] Grub not updating boot configs

Hey guys.  This is probably going to be a really dumb question, but a) I 
only have limited familiarity with Grub2 and b) I really don't want to 
have to rebuild my SD card image from scratch...again.

I have a Pine64 running 7.3.1611 aarch64, and it started out on kernel 
3.10.101.  I've issued yum update after yum update, and it finally 
dawned on me that it wasn't ever booting into the new kernels I was 
installing.  I have 5 of the 4.x kernels installed, but it's never even 
attempted to boot into them.  I've dug around a little bit, and here's 
what I can see so far:

1)  By RPM list, I don't even have a 3.x kernel installed anywhere. It 
was installed during the initial system image in some way outside of 
RPM/yum, and it hasn't been removed in the time since.
2)  I don't have a grub2.cfg file like my x86_64 systems have.  I have a 
symlink at /etc/grub2-efi.cfg that is supposed to point to 
../boot/efi/EFI/centos/grub.cfg, but that doesn't exist either.
3)  If I run grub2-mkconfig, I can get a seemingly-valid grub2.cfg file 
that only references the 4.x kernels I have installed.  I put that file 
at the symlink target from #2 and rebooted, but it apparently had zero 
impact.  It rebooted just fine...into 3.10.101.

So my question boils down to this:  what exactly am I missing here 
that's preventing this from updating kernels correctly?  Thanks for the 
help.

Mike