ano, bez problemu, "pouze" je potreba podpora na strane initramfs, coz vetsina z tech pouzivanejch dister ma(s tim ze "kazde" do ma jinak)...
bezne to pouzivam na USBFlash kde mam GPT+GrubPartisnu(simulace LegacyBoot)+EFI a nainstalovan Grub-EFI i Grub-PC(Legacy), takze to startuje jak na Legacy tak EFI strojich... v menu pak hromadu polozek pro boot z ulozenych ISO(v adresari /iso, jadro i init neni treba vytahovat rucne, bere se primo z iso)...
priklad Xubuntu, i s ukazkou pouziti definovani funkce a promenych a blokovani nekterych SyStEmD sluzeb nevhodnych pro live:
probe -u $root --set=rootuuid # pro tohle konkretni ISO (resp. *buntu) netraba, ale ponechavam pro pripad kdy bys narazil na distro co pozaduje uvedeni konkretniho zarizeni z ktereho ma iso brat set device="/dev/disk/by-uuid/$rootuuid" export device function mount_x18041_amd64_t { set isofile="/iso/xubuntu-18041-amd64.t.iso" loopback loop $isofile set defbuntu="iso-scan/filename=$isofile locale=en_US.UTF-8 forcepae net.ifnames=0 file=/cdrom/preseed/xubuntu.seed boot=casper i8042.noloop=1 i8042.nomux=1 reboot=c" export deftester set systemdmask="systemd.mask=dev-hugepages.mount systemd.mask=dev-mqueue.mount systemd.mask=sys-fs-fuse-connections.mount systemd.mask=sys-kernel-config.mount systemd.mask=sys-kernel-debug.mount systemd.mask=tmp.mount" export systemdmask } menuentry "Xubuntu 18.04.1 AMD64" { mount_x18041_amd64_t linux (loop)/casper/vmlinuz quiet splash $defbuntu $systemdmask initrd (loop)/casper/initrd }