lukvdl wrote: ↑Fri Feb 02, 2024 6:31 pm
Actually on it : Ubuntu 22.04.3 LTS.
Now I want to change to Puppy Linux Slacko64 Puppy 7.0, of which I have the iso on a bootable USB.
I wanted to change the boot order, but I do not see the USB mentioned in the BIOS/UEFI.
Post a photo of the BIOS/UEFI screen to show the window of that about boot order management. I'm surprised if none of the entries are for USB booting. Maybe called USB harddrive?
As @rockedge said, an alternative would be to make a frugal install of your Slacko64 Pup on the internal hard drive and arrange for Ubuntu grub2 to boot it via some new grub2 menu stanza put into Ubuntu filesystem in file, usually named: /etc/grub.d/40_custorm
If you have the iso on that usb, you could in theory also manage to boot it via Ubuntu boot menu using a suitable boot from iso grub2 menu stanza put into Ubuntu filesystem /etc/grub.d/40_custom
For that boot from iso on usb, you'd first have to determine the UUID of the usb stick (or know its LABEL), which you can find with blkid command. Then you'd use a menu stanza edited into /etc/grub.d/40_custom that would be something like. EDIT: below method didn't involve need to determine UUID or LABEL):
Code: Select all
menuentry 'Slacko Pup' {
set isopath='/BOOTISOS/slacko.iso'
search --no-floppy --file --set=root $isopath
loopback loop $isopath
linux (loop)/vmlinuz boot=live config iso-scan/filename=$isopath noprompt noeject
initrd (loop)/initrd.gz
}
or if above more generic try doesn't work, determine which partition and then use that partition (such as hd1,0 or hd1,1) as follows:
Code: Select all
menuentry 'Slacko Pup' {
set isopath='/BOOTISOS/slacko.iso'
loopback loop (hd1,1)$isopath
linux (loop)/vmlinuz boot=live config iso-scan/filename=$isopath noprompt noeject
initrd (loop)/initrd.gz
}
Once you have the iso basically booting, you could probably modify the grub menu linux line to include pmedia and pfix info at the end like: pmedia=cd pfix=nocopy or whatever you want. I'm afraid I no longer remember Puppy boot arguments well at all.
You might additionally need the likes of:
insmod part_msdos
insmod ext2
as first two lines of the menuentry.
NOTE: I have just typed above from memory (actually cherrytree notes), but haven't had time to try using actual iso on usb stick. Also, I put path on usb stick to the iso as /BOOTISOS/slacko.iso above. You need to change that to suit your actual installation.
IMPORTANT FINAL STEP
Finally, you need to boot into the Ubuntu distro and run the command: sudo update-grub to actually make the 40_config entry active in main grub menu. If you later want to change the boot order, the file to do that is /etc/default/grub. In there, from memory, you change the GRUB_DEFAULT=0 to maybe GRUB_DEFAULT=1 (being whichever position your distro of interest is in). But leave that order of boot change till after you have the iso successfully booting! 
Above menu stanzas may well need some fixing so keep posting results and someone should finish this job off for you.
NOTE WELL: If you ever want to similarly boot a Kennel Linux (KL) distro using method like the above, see the following post and modify above stanzas accordingly: https://forum.puppylinux.com/viewtopic. ... 641#p97641
aboard, @lukvdl!