boot an alternate kernel

[Bob]

** Reply to message from Ralf Mardorf via ubuntu-users
<ubuntu-users at lists.ubuntu.com> on Thu, 26 May 2022 20:39:39 +0200

> On Thu, 2022-05-26 at 20:31 +0200, Ralf Mardorf via ubuntu-users wrote:
> > On Thu, 26 May 2022 20:23:41 +0200, Ralf Mardorf wrote:
> > > > Should it work from only one partition or should it work from either
> > > > partition?  
> > 
> > > You probably installed GRUB 2 times. One is the GRUB used by the boot order
> > > of your BIOS settings, the other GRUB is unused. You are likely booted
> > > to the wrong install and generating the menu.cfg for the unused GRUB.
> > 
> > In your case it's likely possible that you can use both GRUB
> > bootloaders, but you need select one bootloader by the BIOS' setting
> > boot order and you need to update the menu.cfg of both GRUB.
> 
> IOW actually you need to update only one menu.cfg. The one of the disk
> that is selected by the 1st drive of the BIOS boot order. To do this you
> need to run the install of this GRUB, not the install of the unused
> GRUB. It's not possible to do this from the other install by a
> systemd-nspawn or by a "regular" chroot. Actually you could copy the
> menu.cfg from one to the other install.

Thank you for the information.  Still not sure I understand all of it yet.

The computer is a Lenovo IdeaCentre 5.  It came with windows already installed
on an SSD drive.  I installed Ubuntu on the HDD.

SDA1 is the grub partition
SDA2 is a small Ubuntu test partition.  Home and root in the same partition.
SDA6 Is a FAT32 drive shared by all the operating systems.
SDA7 Is /home for SDA9.
SDA8 Is swap.
SDA9 Is the default boot partition - Ubuntu root

Since there is only one grub partition I assumed that updating grub would keep
everything current.  With this current problem it does not seem to work that
way.  Updating from SDA9 did not update the grub menu but updating from SAD2
did update the grub menu.  Which means the I have been lucky since I got this
system in that nothing broke boot previously, it just may have not booted the
latest kernel for SDA9.

-- 
Robert Blair


Giving money and power to government is like giving whiskey and car keys to teenage boys.  -- P.J. O'Rourke, Civil Libertarian