I located iso file on (hd0,gpt7)/iso/ubuntu-20.10-desktop-amd64.iso
On GRUB commandline, I typed like below.
set root=(hd0,gpt7)
set iso=/iso/ubuntu-20.10-desktop-amd64.iso
loopback l $iso
linux (l)/casper/vmlinuz root=casper iso-scan/filename=$iso
initrd (l)/casper/initrd
boot
Ubuntu booted. But could not installed Ubuntu with error. It took so many hours checking system.
Best Answer
Installing Ubuntu to Internal HDD from ISO booted on the HDD
Your /boot/grub/grub.cfg file should have a menuentry similar to:
The
toram
item is critical.Boot the computer selecting the above menuentry.
Unmount all partitions. To unmount the Live iso run:
sudo umount -lrf /isodevice
Confirm all partitions are unmounted. You should be running totally in RAM.
Run the Ubuntu installer. I generally use the Something else option.
You may want to run
sudo update-grub
on reboot.