On Mon, 23 Nov 2015 10:48:35 +0200 Angelo Moreschini mrangelo.fedora@gmail.com wrote:
using GParted I can have a full information about all the HDs on the computer.. :
[snip]
At this point I think to know that there are two HDs bootable on the computer (because these have the "partition tables" activated): WDC WD5000AZRX-0 ----- partition sdb1 WDC WD5000AZRX-0 ----- partition sdc1
But .. my acknowledge about Grub is no so very very good, and I would beg to be helped to understand as grub can work in a such situation. This in order to concretely be able to solve this problem (that look to be no so much trivial...).
I'm not an expert on grub2 either. But now that you know which disk is which, you can change the boot order in the bios so that the disk you want to boot from is first. If it fails, try the other bootable disk. If both fail, then grub2 is not installed properly on those disks, and you can boot with your tried and true workaround, and ask here again, or look at the documentation.
The documentation for grub2 is in info format, and if you install a package called pinfo, you can easily navigate through the pages. My recollection is that there is a lot of it, but that I found it somewhat unclear. But I was able to get it to work using the documentation.
Anyhow, there is no harm in trying the boot, and if it works, then you are done without having to delve further into the workings of grub2.