How to have a custom UEFI grub menu for a multiboot system

English Install/Boot/Login
2

That misfeature is easily worked around by specifying no swap installing Debian, then after installation is complete adding swap to fstab manually. Something I never seem to remember to try is turning existing swap on before letting the Debian installer proceed, to see if the installation process will skip wanting to format it.

My custom.cfg files are somewhat simpler than yours, omitting obfiscatory options and human immemorable UUIDs, e.g.:

menuentry "memtest86 7.4 EFI" {
	search --no-floppy --label --set=root K25P01ESP
	chainloader /mt74x64.efi
}
menuentry "openSUSE TW defkernel" {
	search --no-floppy --set=root --hint-bios=hd0,gpt7 --label k25p07stw
	linux	/boot/vmlinuz root=LABEL=k25p07stw noresume
	initrd	/boot/initrd
}
menuentry "openSUSE 15.0 defkernel" {
	search --no-floppy --set=root --hint-efi=hd0,gpt8 --label k25p08s150
	linux	/boot/vmlinuz root=LABEL=k25p08s150 noresume
	initrd	/boot/initrd
}
menuentry "openSUSE 15.1 defkernel" {
	search --no-floppy --set=root --hint-efi=hd0,gpt9 --label k25p09s151
	linux	/boot/vmlinuz root=LABEL=k25p09s151 noresume
	initrd	/boot/initrd
}
menuentry "Debian 10 Buster defkernel" {
	search --no-floppy --set=root --hint-baremetal=ahci0,gpt10 --label k25p10deb10
	linux	/boot/vmlinuz root=LABEL=k25p10deb10 noresume
	initrd	/boot/initrd
}
menuentry "Debian 10 Fat Buster defkernel" {
	search --no-floppy --set=root --hint-baremetal=ahci0,gpt11 --label k25p11deb10fat
	linux	/boot/vmlinuz root=LABEL=k25p11deb10fat noresume
	initrd	/boot/initrd
}
menuentry "Tubuntu 18.04 defkernel" {
	search --no-floppy --set=root --hint-baremetal=ahci0,gpt12 --label k25p12Ubionic
	linux	/boot/vmlinuz root=LABEL=k25p12Ubionic noresume
	initrd	/boot/initrd
}

I don’t bother with the execute bits in /etc/grub.d/. 06_custom makes custom.cfg entries first, so the cruft grub2-mkconfig generates doesn’t really matter, while keeping it retains easy access to prior kernels.

All my MBR PCs boot from generic MBR code and openSUSE Gfxboot Grub 0.97-203.7 or older on a small primary partition with self-generated menu.lst, roughly similar to above custom.cfg, and penguin=100. :slight_smile:

This thread probably ought to be in Unreviewed How To and FAQ