GRUB doesn't boot all kernels

blind Pete 0123peter at
Thu Jul 14 07:49:18 UTC 2016

Ralf Mardorf wrote:

> On Sun, 10 Jul 2016 21:40:24 +1000, blind Pete wrote:
>>It could be the kernel rather than grub.
> That's possible, after several Arch Linux upgrades, the same kernel
> build for Arch Linux doesn't provide proper real-time abilities
> anymore, but it's still possible to boot it.
> I wonder why it was possible to build the kernel for 16.04 without
> getting an error message.

Definite, "don't know".  Sorry.  

> FWIW this is the script that "successfully" build the kernel packages:
> Pastebin takes a while, because the script starts with the config.
> The comment on top of the script is a reminder, mentioning that it's
> the same kernel I build 2015, running without issues on 15.10. Once
> pastebin is ready, scroll to the end of the script, to skip the config.
>>BIOS or UEFI firmware?

Important distinction for boot questions.  

That implies that you are using an mbr formatted disk.  
It is technically possible to boot a BIOS system from 
a drive with a GNU Partition Table, but I recommend 
against it.  

>>Grub classic or grub2?
> Ubuntu 16.04, GRUB2
>>How many installations do you have?
> A lot, but I'm just using a few, so I don't know which actually still
> work. But Ubuntu 16.04, formerly 15.10, Arch, FreeBSD and a very old
> Suse install are used and should work. FreeBSD is broken, after GRUB
> was installed by the release upgrade from 16.04 to 15.10. before the
> upgrade no GRUB package was installed for the Ubuntu install.
>>Which one updated grub most recently?
> Actually I write grub.cfg manually, just for testing purpose I run
> grub-mkconfig for the Ubuntu install.

It is easy to lose track of which installation, and bootloader, has 
control of the mbr.  Then you have to remember to rewrite the mbr 
from the correct installation so that the expected binaries and 
configuration files are found and acted upon.  

Is the command to write to the mbr "grub-install"?  I don't have 
grub classic or grub2 installed on this machine.  

Interesting partially working things happen when the last thing 
that wrote to the mbr was not the thing that you thought was 
the last thing to write to the mbr.  

I'm not as much help here as I wanted to be.  Hopefully I have 
asked the right question.  

> Regards,
> Ralf
blind Pete
Sig goes here...  

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