grub loader upgrading

At grub loader upgrading (2.88) with i386 wheezy I was (in perspetive,
please see below) rather confused at the warning:

<It is possible to install grub to partition boot record ... however,
this forces grub to use the blocklist mechanism, which makes it less
reliable, and therefore is not recommended>

I had no problem in this case. Having "/dev/sda1  /boot" I selected
"[*] /dev/sda", although I would have appreciated a recall that the
choice is made through the press bar.


As the grub-choice request comes without giving the opportunity to go
back, or do nothing, I would appreciate advice how to do for grub
loader upgrading with  the raid1 amd64 wheezy server, as I have no
maintainer. In this case:

/dev/md0   /boot

/dev/mapper/vg1-home      /home

etc

Will the choice be given unequivocally for "dev/md0"?

Naive as the question is, it poses problems to me, having already had
so many problems with the nvidia driver  for cuda applications and the
related bash-dash. So that I do no upgrading until the grub procedure
is clear to me.

thanks

francesco pietra