I've finally solved my problem. Looking for someone else having troubles with USB disks like mine, I found this thread: http://community.wdc.com/t5/My-Passp...ux/td-p/370439. The guy in the last post suggests to keep grub below cylinder 1023, and so I did. Now grub2 works fine: it seems that the silliest solution was the right solution in this case. I also suppose that most of the issues were coming from my USB drive rather than from grub2, so let's give the devil his due

Wow, a lot of great info.

Did you by anychance use the "symbolic" menu entry for Debian based OS's that I posted? I am just curious about that. They are all I use as it keeps my menu short and sweet.

You can have 2 entries per OS if you want. Just edit the instruction string to read "..... ro single" dropping every thing else. I never do it is shorter without it, editing the entry to read that way for one boot is fast (how often do you need recovery mode?).

I think that may cure the file system problem. Really sounds like a script problem to me, makes me wonder about the integrety of your grub install.

There is a slight chance, but a chance none the less, of malware infecting your MBR. Testdisk will right new, blank, code to the MBR if you think that at all a possibility. You will, of coarse, have to reinstall grub to your MBR after that.

Ubuntu started using Grub2 first (as default boot loader) of any distro. I was testing the dev release version of 9.10 when that was introduced one day right after alpha 2. No documentation. What a ride. We, the testers, spent 2 weeks editing the grub.cfg file directly to tweak things. Slowly learned how to deal with it.

That first iteration we got would not boot the OS it was on if the OS was installed on 2 partitions. A single partition install would boot other installs that were installed on 2 partitions. Just plain weird.

The Ubuntu community documentation is the best for Debian based installs using grub-pc. RH branch installs do not even use the same commands to install or update grub.
https://help.ubuntu.com/community/Grub2

The best thread to get on to for answers to the stickiest problems is on the UFs, if you can stand that outfit.
http://ubuntuforums.org/showthread.php?t=1195275

The OP there was one of the testers in 9.10-testing. Did a lot of research and shared it. Did and continues to do a lot of experimentation with grub-pc. Pulled all of the discoveries that all of us made and started the basis for that linked thread on the testing forum.

He is also the main perpetrator of the Ubuntu Community link I posted.

While I have given up on Ubuntu and particularly their Officail Forums, there are people and threads I miss there. Drs305 and his many threads on how to make grub-pc sit up and beg being at, or at least near, the top of the list.

Now that is really cool. A lot of problems come from bios. Have had trouble with this Dell box bios at times.

Am not a big user of /boot partitions as I do not dual boot, I multi boot with many Linux installs. I like to swap the grub duties between them to make sure all are working.

That post, however, will be copied to the file on such things that I keep. Will be trying it out soon myself to verify that it works on my hardware.

Thank you very much.

I am one of those folks that really loved grub-legacy but was aware of the many problems with keeping it up to the new file systems and bootable media that seem to come out every other month.

Grub-pc is really much more adaptable to these things.

Will, with full attribution, be passing this on.

Thanks again.

For posterity: after literally months of lazy trials and errors, I've managed to make Grub2 go in graphical mode. Testing grub with:

I've noticed an almost invisible (due to normal boot speeds) error about a "/boot/grub2/unicode.pf2" file not found. After a simple symbolic linking from "/usr/share/grub/unicode.pf2", Grub2 went into graphical mode.