I tried to revert to an older kernal on my own but unfortunately I have gotten tangled up and need help to proceed. This is not an emergency but would appreciate any help as I am trying to learn from my mistakes, etc.
Below is my terminal output as I tried to take steps to revert to an older kernal as the default in the grub. The formatting came across a little strange.
zMac:~$ lsb_release -a
No LSB modules are available.
Distributor ID: Zorin
Description: Zorin OS 16.3
Release: 16
Codename: focal
zMac:~$ dpkg -l | grep linux-image
rc linux-image-5.11.0-27-generic 5.11.0-27.29~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-27-generic 5.13.0-27.29~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-28-generic 5.13.0-28.31~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-30-generic 5.13.0-30.33~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-35-generic 5.13.0-35.40~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-39-generic 5.13.0-39.44~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-40-generic 5.13.0-40.45~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-41-generic 5.13.0-41.46~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-44-generic 5.13.0-44.49~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-48-generic 5.13.0-48.54~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-51-generic 5.13.0-51.58~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-52-generic 5.13.0-52.59~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-41-generic 5.15.0-41.44~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-43-generic 5.15.0-43.46~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-46-generic 5.15.0-46.49~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-48-generic 5.15.0-48.54~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-50-generic 5.15.0-50.56~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-52-generic 5.15.0-52.58~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-53-generic 5.15.0-53.59~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-56-generic 5.15.0-56.62~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-57-generic 5.15.0-57.63~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-58-generic 5.15.0-58.64~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-60-generic 5.15.0-60.66~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-67-generic 5.15.0-67.74~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-69-generic 5.15.0-69.76~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-71-generic 5.15.0-71.78~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-72-generic 5.15.0-72.79~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-73-generic 5.15.0-73.80~20.04.1 amd64 Signed kernel image generic
ii linux-image-5.15.0-76-generic 5.15.0-76.83~20.04.1 amd64 Signed kernel image generic
ii linux-image-5.15.0-78-generic 5.15.0-78.85~20.04.1 amd64 Signed kernel image generic
ii linux-image-generic-hwe-20.04 5.15.0.78.85~20.04.38 amd64 Generic Linux kernel image
zMac:~$ uname -srn
Linux zMac 5.15.0-78-generic
zMac:~$ dpkg -l | grep linux-image| grep -v hwe
rc linux-image-5.11.0-27-generic 5.11.0-27.29~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-27-generic 5.13.0-27.29~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-28-generic 5.13.0-28.31~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-30-generic 5.13.0-30.33~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-35-generic 5.13.0-35.40~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-39-generic 5.13.0-39.44~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-40-generic 5.13.0-40.45~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-41-generic 5.13.0-41.46~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-44-generic 5.13.0-44.49~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-48-generic 5.13.0-48.54~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-51-generic 5.13.0-51.58~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.13.0-52-generic 5.13.0-52.59~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-41-generic 5.15.0-41.44~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-43-generic 5.15.0-43.46~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-46-generic 5.15.0-46.49~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-48-generic 5.15.0-48.54~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-50-generic 5.15.0-50.56~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-52-generic 5.15.0-52.58~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-53-generic 5.15.0-53.59~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-56-generic 5.15.0-56.62~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-57-generic 5.15.0-57.63~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-58-generic 5.15.0-58.64~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-60-generic 5.15.0-60.66~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-67-generic 5.15.0-67.74~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-69-generic 5.15.0-69.76~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-71-generic 5.15.0-71.78~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-72-generic 5.15.0-72.79~20.04.1 amd64 Signed kernel image generic
rc linux-image-5.15.0-73-generic 5.15.0-73.80~20.04.1 amd64 Signed kernel image generic
ii linux-image-5.15.0-76-generic 5.15.0-76.83~20.04.1 amd64 Signed kernel image generic
ii linux-image-5.15.0-78-generic 5.15.0-78.85~20.04.1 amd64 Signed kernel image generic
zMac:~$
zMac:~$ uname -srnm
Linux zMac 5.15.0-78-generic x86_64
zMac:~$ cat /boot/grub/grub.cfg | grep -iE "menuentry 'Zorin, with Linux" | awk '{print i++ " : "$1, $2, $3, $4, $5, $6, $7}'
0 : menuentry 'Zorin, with Linux 5.15.0-78-generic' --class zorin
1 : menuentry 'Zorin, with Linux 5.15.0-78-generic (recovery mode)'
2 : menuentry 'Zorin, with Linux 5.15.0-76-generic' --class zorin
3 : menuentry 'Zorin, with Linux 5.15.0-76-generic (recovery mode)'
zMac:~$ uname -srnm
Linux zMac 5.15.0-78-generic x86_64
zMac:~$ cat /etc/default/grub
If you change this file, run 'update-grub' afterwards to update
/boot/grub/grub.cfg.
For full documentation of the options in this file, see:
info -f grub -n 'Simple configuration'
GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR=lsb_release -i -s 2> /dev/null || echo Debian
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""
Uncomment to enable BadRAM filtering, modify to suit your needs
This works with Linux (no patch required) and with any kernel that obtains
the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"
Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console
The resolution used on graphical terminal
note that you can use only modes which your graphic card supports via VBE
you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480
Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true
Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"
Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"
GRUB_THEME=/usr/share/grub/themes/zorin/theme.txt
zMac:~$ grep GRUB_DEFAULT /etc/default/grub
GRUB_DEFAULT=0
zMac:~$ sudo vi /etc/default/grub
(My comments: At this point, I wanted to change the GRUB_DEFAULT above to [2 : menuentry 'Zorin, with Linux 5.15.0-76-generic' --class zorin] but I could not get the terminal to accept my edits. It just didn’t recognize my keystrokes. In hindsight, I think there was an edit mode I needed to go into. But after using my directional keys and clicking on something I apparently shouldn’t have my previous terminal history disappeared and was replaced with the following from which I don’t know how to proceed.
I have tried starting over but upon getting to issuing sudo vi /etc/default/grub it goes directly to the error message below. Any suggestions on how I can revert to the older kernal from here.)
E325: ATTENTION
Found a swap file by the name "/etc/default/.grub.swp"
owned by: root dated: Sun Aug 06 15:57:10 2023
file name: /etc/default/grub
modified: YES
user name: root host name: guy-iMac
process ID: 2763
While opening file "/etc/default/grub"
dated: Mon Jul 17 21:08:38 2023
(1) Another program may be editing the same file. If this is the case,
be careful not to end up with two different instances of the same
file when making changes. Quit, or continue with caution.
(2) An edit session for this file crashed.
If this is the case, use ":recover" or "vim -r /etc/default/grub"
to recover the changes (see ":help recovery").
If you did this already, delete the swap file "/etc/default/.grub.swp"
to avoid this message.
"/etc/default/grub" 35 lines, 1260 characters
Press ENTER or type command to continue
(My comments: any keystroke or even mouse wheel movement takes me to the following.)
If you change this file, run 'update-grub' afterwards to update
/boot/grub/grub.cfg.
For full documentation of the options in this file, see:
info -f grub -n 'Simple configuration'
GRUB_DEFAULT=0
GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=0
GRUB_DISTRIBUTOR=lsb_release -i -s 2> /dev/null || echo Debian
GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"
GRUB_CMDLINE_LINUX=""
Uncomment to enable BadRAM filtering, modify to suit your needs
This works with Linux (no patch required) and with any kernel that obtains
the memory map information from GRUB (GNU Mach, kernel of FreeBSD ...)
#GRUB_BADRAM="0x01234567,0xfefefefe,0x89abcdef,0xefefefef"
Uncomment to disable graphical terminal (grub-pc only)
#GRUB_TERMINAL=console
The resolution used on graphical terminal
note that you can use only modes which your graphic card supports via VBE
you can see them in real GRUB with the command `vbeinfo'
#GRUB_GFXMODE=640x480
Uncomment if you don't want GRUB to pass "root=UUID=xxx" parameter to Linux
#GRUB_DISABLE_LINUX_UUID=true
Uncomment to disable generation of recovery mode menu entries
#GRUB_DISABLE_RECOVERY="true"
Uncomment to get a beep at grub start
#GRUB_INIT_TUNE="480 440 1"
GRUB_THEME=/usr/share/grub/themes/zorin/theme.txt
~