How to Update grub

[wdewindt]

This thread I started from a while back I believe will give you some guidance:

Critical grub-install failure. Systems possibly non-bootable?

Greetings! As I was wrapping up the usual batch of updates / upgrades on my systems before the holidays, I encountered a seemingly critical problem with my pair of ROC-RK-3328-CC (Renegade) boards. I ran apt-get update as usual and then apt-get upgrade on them both. The upgrade command warned me that the updated kernel was being held back, which it always does, but I allowed it to continue as I usually upgrade the kernel standalone after the other packages. When the upgrade process ran, on both…

About midway through the thread is the discussion of manually running grub updates.

Cheers!