 remove universe from the partner repos line. (re @Rodrigo: this is the output of cat /etc/apt/sources.list:
 # Automatically generated by Calamares on 2023-10-20.
 # Lines starting with "deb" are mandatory, while lines starting with "deb-src"
 # are for more detailed package information.
 
 ## See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
[22:14] <cristian_c> hi
[22:15] <cristian_c> I've made a new installation of lubuntu 23.10 with a ia32 uefi
[22:16] <cristian_c> of course, I've not installed grub/bootloader and I can't boot lubuntu if I don't install that properly
[22:16] <cristian_c> I've made several attempts but I don't know how trobuleshooting this stuff
[22:16] <cristian_c> any ideas?
[22:17] <diogenes_Vx15> cristian_c, 'I've not installed grub' <<< why?