Upgrade failed, black screen of grub, MBR busted

There I was, having a pretty good time. To me, that means having spent most of the weekend playing table tennis with my son, and finalizing the movement of all my VMs to the shiny new ESXi server.

To make things perfect, I wanted all the machines to run VMWare tools. On some machines that was as simple as selecting the appropriate menu item.

However, in some other cases it was simply not that simple. I needed to do the whole thing manually. For now, I’ll skip over the details of that and cut to the chase.

I tried to upgrade my kernel so I could recompile some vmware tools drivers when something went terribly wrong.

When I rebooted, all I had was a black screen saying “GRUB _” and it didn’t accept a single key stroke.

Luckily, it wasn’t the most important machine, but still – things didn’t look too good.

After spending some time on google, I found that others had had the same problem, and it seemed to having to do with the MBR (Master Boot Record) being messed up. It made kind of sense, but what then?

A thread I found on an Ubuntu site mentioned something called the Super Grub Disk. I downloaded it from http://www.supergrubdisk.org/ and uploaded it to the ESXi data storage.

Add a CD to the VM and point it to the ISO image.

Next – how to get the VM to change boot sequence?

Shut down the VM, edit settings and check the little box.

Save and reboot.

The interface is somewhat different – but plain menu driven! For me, it worked to simply select the menu options with help, select language, opt for Gnu/Linux and then “Fix boot of Gnu/Linux (GRUB)”. 0.1 seconds later I got an OK message, shut down the machine and switched back the boot order.

It just worked, The machine is back online. Now it’s time to beat the next generation in table tennis one more time before I install the VMWare tools.

A piece of advice: Take snapshots before you upgrade the kernel!

–Jesper Hogstrom