I created a bootable USB with Rufus using Lubuntu 20.10 amd64 desktop iso image. I already have installed on my desktop Lubuntu 16.04.
I change the boot options in BIOS to boot from USB first and then i receive the following message:
Welcome to GRUB!
error: symbol ‘grub_calloc’ not found.
Entering rescue mode…
I try now creating another usb bootable stick using Unetbootin. I will let you know if it is working.