Unable to install GRUB in dummy

[David Wright]

i install with debian-12.10.0-amd64-netinst.iso
during final stage of installation, it fails to install grub
"Executing 'grub-install dummy' failed."
"This is a fatal error."
how to solve it?

Presumably that error message was from the screen. Have you looked
at /var/log/installer/syslog for more expansive error messages?

Cheers,
David.

[Andrew M.A. Cater]

Post by David Wright
Presumably that error message was from the screen. Have you looked
at /var/log/installer/syslog for more expansive error messages?
Cheers,
David.

Thank Wright! i have solved it on my own
i am new user of gpt, fatal error is caused by my failure to create efi
partition

Make it simple for yourself. If you are at all unsure when you install,
just take guided partitioning.

That should set up a 512M partition for boot, a 1G partition for swap
and the rest of the disk for /

Unless you *really have* to partition things yourself, putting everything
in one partition will normally work. Once you've done this a few times
and know what you want, then you can partition separate space for /var
or whatever.

GPT and UEFI is the way forward on machines that support them.

it seems both installer and i are quite dumb
in the end i use mbr, as one of my PCs doesn't support gpt
btw what is recommended size of efi partition?
default size is 512M

All the very best, as ever,

Andrew Cater
(***@debian.org)

[Max Nikulin]

in the end i use mbr, as one of my PCs doesn't support gpt

It depends on firmware, but I expect that UEFI spec describes
requirements for ESP in the case of MBR partitions.

btw what is recommended size of efi partition?
default size is 512M

sgdisk(8)

* Boot disks for EFI-based systems require an EFI System
Partition (gdisk internal code 0xEF00) formatted as
FAT-32. I recommended making this partition 550 MiB.
(Smaller ESPs are common, but some EFIs have flaky FAT
drivers that necessitate a larger partition for reliable
operation.) Boot-related files are stored here. (Note
that GNU Parted identifies such partitions as having the
"boot flag" set.)

A week ago Jeffrey posted the following link
<https://wiki.debian.org/UEFI#EFI_System_Partition_.28ESP.29_recommended_size>
with other sources and recommendations.

[David Wright]

Post by David Wright
Presumably that error message was from the screen. Have you looked
at /var/log/installer/syslog for more expansive error messages?

Thank Wright! i have solved it on my own
i am new user of gpt, fatal error is caused by my failure to create
efi partition
it seems both installer and i are quite dumb

Or you didn't look at the Installation Guide.

in the end i use mbr,

I presume that means that you are BIOS-booting.

as one of my PCs doesn't support gpt

I'm surprised. I BIOS-boot my 20-yr old laptop into linux running on a
GPT disk, and I scrapped a similar but older desktop too. Grub is
installed in the protective MBR of the GPT disk, so the BIOS boots
the MBR in the same way as if the disk was MBR-partitioned.

btw what is recommended size of efi partition?
default size is 512M

That's what I use (they're linux-only computers):

Filesystem IUse% Type 1MB-blocks Used Avail Use% Mounted on
/dev/sda2 - vfat 520 24 496 5% /boot/efi

My BIOS-booting computers have a similarly-sized partition, but used
as swap. It's there so that the disk is future-proofed for used with
a UEFI computer.

Other OSes might put other stuff in /boot/efi/; I don't know any details.

Cheers,
David.