Grub reinstall - finding the correct disk

[soundofthunder]

@Kobold

He will lose all data not only a partition on that disk

Yes, as was inferred by the word sacrifice. I’ll come back to this when I have an opportunity, that is, if the OP isn’t further confused by differing opinions in the meantime.

Enjoy Xmas, if that’s something you do. Cheers.

@soundofthunder

If you choose UEFI, then you need to disable CSM in the BIOS to boot UEFI exclusively, and sacrifice the Legacy disk and its contents (save any data you need to USB, or similar).

[megavolt]

@mark

I won’t be able to do this at the beginning of the disk. Do I have to do something differently if it is is not at the beginning? Can the partition be part of an extended partition?

So wie are talking about sda5 right? That is Manjaro?

Usually grub can find the partition which flagged with bios_grub. That one can also be at the end, but maybe the UEFI needs that.

GPT can have up 128 primary partitions. No need for LBA.

@mark

I would like to stay with BIOS instead of EFI. I just don’t want to have more things to check. With BIOS I know that it works.

Well then stay with it and limit yourself.

@Kobold

@Kobold

I personaly think that MBR is superior to this stupid UEFI features anyways… its a big downgrade related to security… applications or a virus can change your UEFI settings while the good old Bios is still protected, is a big plus to NOT use EFI.

I hear you, but note that even if you run in compatibility mode on a UEFI, it is still UEFI, only with a BIOS emulation. Its like starting a PSX emulator, instead of running real hardware.

[Kobold]

@megavolt

Well then stay with it and limit yourself.

Yeah he should limit himself… and archive the full experience with possible dangerous Voltage changes from Drivers? /sarcasm off

German AMD issue Topic:

Radeon Adrenalin: Grafiktreiber übertaktet AMD Ryzen ungefragt über das BIOS

[Teo]

To me it seems you are booting from the mbr on the B disk, even if the manjaro is on the gpt A disk. That is why there is no uefi esp on the A disk.

[mark]

@soundofthunder

You can reconnect it later when Manjaro is installed.

I do have a running Manjaro installation and don’t want to reinstall Manjaro.
I do not want to scarify any disk either. That is why I ask before I do something stupid.

I want to use BIOS not EFI.

@megavolt

Create a 10MiB unformatted partition (preferably at the beginning of the disk), flag it with bios_grub and name it bios-grub (so you know later what that is). With this partition you can write the MBR on a GPT partition table, when running grub-install.

Assuming I can create a partition like that (I cannot try right now because I wouldn’t have enough time for troubleshooting).

Would the next command write automatically to this partition?

@mark

grub-install --force --target=i386-pc --recheck --boot-directory=/boot /dev/sdy

It feels so dangerous running a command on an entire disk. What would that command do if it does not find a partition like mentioned above?

If that command worked and I did

grub-mkconfig -o /boot/grub/grub.cfg

Would this be sufficient? Or do I have to do something else? Would this do anything to the other disk?

Thanks for the help already.

[megavolt]

@Kobold

Yeah he should limit himself… and archive the full experience with possible dangerous Voltage changes from Drivers? /sarcasm off

Keep it calm. The whole topic you linked is 100% Windows related.

[Kobold]

Yes it is… and? The Situation is still no differend, a application/driver/virus under OS (if its Linux or Windows, doesn’t matter) has FULL Access to your UEFI settings and this is my Point and is a true fact.

There are FEATURES in Hardware today, that other’s would call it bug or issue.

Happy Xmas everyone

[megavolt]

@mark

Would the next command write automatically to this partition?

@mark

grub-install --force --target=i386-pc --recheck --boot-directory=/boot /dev/sdy

@mark

It feels so dangerous running a command on an entire disk. What would that command do if it does not find a partition like mentioned above?

Only one MBR can be written per disk. And Grub is smart enough to detect MSDOS and GPT. In case of GPT it will write to bios_grub partition, if not there, it will fail.

Anyway… if you don’t have time, then don’t change it. Reinstaling is needed when Manjaro’s grub manages booting.

[Teo]

The command above: sdy will be sdb in your case.

[soundofthunder]

@mark

I want to use BIOS not EFI.

It’s your choice, of course; albeit the wrong choice, in my opinion. If your machine is UEFI-capable, and with the Windows installation already on a GPT partitioned drive, going fully UEFI seems like a no-brainer as is often said.

However, I won’t attempt to dissuade you; there are already too many competing opinions in the thread.

Good luck.

[linux-aarhus]

This topic has been created to address such doubts

[root tip] [How To] Primer on handling a grub package update

How To update the system boot after updating grub itself With the grub update 2023-12-22T23:00:00Z (UTC) to v2.12, it was thus advised to ensure all parts of grub on the system are populated with the new binary and updated configuration. This has revealed that a lot of users have doubts on how to correctly identify if their system needs special handling e.g. identifying whether to use EFI or BIOS commands. This topic is aimed at being a primer to properly assess how to update grub on a syste…

[mark]

@linux-aarhus

This topic has been created to address such doubts

Thanks a lot. This is helpful.

lsblk -o path,pttype,parttypename | grep -e 'dos' -e 'BIOS'
/dev/sdb  dos    
/dev/sdb1 dos    HPFS/NTFS/exFAT
/dev/sdb2 dos    HPFS/NTFS/exFAT
/dev/sdb3 dos    W95 Ext'd (LBA)
/dev/sdb4 dos    Compaq diagnostics
/dev/sdb5 dos    HPFS/NTFS/exFAT
/dev/sdb6 dos    Linux
/dev/sdb7 dos    Linux s

This is the output of the command. If I interpret the results correctly I have an mbr system. So no need to have a new partition because it is written to the mbr?

I think I never changed something about grub when I put the hd in the laptop. I just changed the boot order. It is set to the samsung HD (sdb).

[linux-aarhus]

If that device /dev/sdb/ is the first in your firmware boot order then MBR would be in that device’s MBR.

Assuming the above is correct - this would be the command to sync the disk grub with the new version

 grub-install --target=i386-pc --recheck /dev/sdb

Also see Install-grub: a new way to keep your EFI/MBR in-sync with grub package