F7-x86-64 Stopped Booting - GRUB Issue - Fixed!

[Raymond C. Rodgers]

Tim wrote:
> This seems odd, as I've seen no evidence to suggest that the boot sector
> gets altered by updating a kernel, when you're using grub as your
> bootloader.  After all, you can use the same boot record to boot either
> kernel, and since the changes are in the grub.conf file, there's no need
> to make changes elsewhere, as well.  Lilo's another matter, though.
>
> I can, quite easily, believe that Windows may have simply stuffed the
> file up that you'd previously used through NTLDR.
>
> I think the obvious test would be to take that boot record file from
> before the kernel update, and compare it to the one after the update.
> Use the "diff" command.
>
> If they are the same, as I expect, that means you're chasing a red
> herring.  If they're not the same, you'd have to work out if that's just
> co-incidental, or if there really are kernel-dependent changes in the
> boot record.
>
>   
Diff just stated that the files are different (after all, they are 
binary files). But going through very quickly with hexdump -C show that 
the first 80 bytes or so of the boot sector files are almost completely 
different. I'm not inclined to believe in a coincidence in this case; I 
have enough evidence convince me if no one else that this was related to 
a kernel change.

As for others' suggestion that I'd have to do this for every kernel 
update, we'll see. I didn't need to put the new boot sector file in 
place after the new kernel came down from yum last night (after I got 
Fedora booting again), and I didn't regularly have to do it before. 
Maybe it's just on major kernel revisions that I'll have to do this. 
Regardless, I at least now what to look for now, and can make the 
"repair" in a couple minutes.

Thanks again!
Raymond