The first part (stage 1) is stored in the first 448 bytes, which is responsible for passing control to the so-called stage 1.5, located a little later in memory. This stage finally loads stage 2 from the /boot folder, and transfers control to it.
The names "stage1", "stage1.5" and "stage2" belong to GRUB Legacy, i.e. GRUB versions 0.xx. When stage 1 is ...
You could do it with wipefs:
wipefs can erase filesystem, raid or partition-table signatures (magic strings) from the
specified device to make the signatures invisible for libblkid. wipefs does not erase the
filesystem itself nor any other data from the device.
I think it helps if you try to walk across the entire chain starting where you as a computer just finished Power On Self Test and have been issued to start an operating system from a particular disk. With MBR you face a lot of historic limitations and have to go very tiny steps and can only do very simple things. With UEFI you have platform drivers that can ...
A GPT partitioned disk still has a legacy MBR that is typically used to store a "Protective MBR", containing an old-fashioned partition table defining a single partition of type EE spanning the whole disk (up to 2 TB). The purpose of this entry is to tell old tools that don't understand GPT that there is no free space on the disk, hopefully preventing the ...
“msdos” does mean MBR, yes. That has no relation to the file systems used, which is where a file size limit would come from.
GPT is fine for an external drive.
The “loop” partition type is used by parted for raw disk access, i.e. when there’s no partition table.
“msftdata” is a parted flag used to indicate that the partition uses the basic data GUID, not ...
If you look at the sources of GRUB, available here, you find stage1 is actually defined at grub/grub-core/boot/i386/pc/boot.S.
It can perform a floppy boot if configured. It does boot from a configured harddisk, and it needs to know which C/H/S it has to load stage1.5 from. The only automatic function it has is determining which drive the boot sector was ...
What you describe is enough to boot Ubuntu and other linux distros in UEFI mode
The UEFI boot system is looking for an EFI system partition (ESP), and it couldn't care less about leftovers from an old BIOS bootloader.
As a matter of fact, you can make a grub BIOS bootloader point to the same grub.cfg file and have a system bootable both in UEFI mode and ...
Reinstall from working (not liveCD/DVD/USB) system - first find Ubuntu drive (example is drive sdb but use your drive not partitions):
sudo parted -l
if it's "/dev/sdb" then just run:
sudo grub-install /dev/sdb
If that returns any errors run:
sudo grub-install --recheck /dev/sdb
Then just to redo menu:
When GRUB boots from a MBR, the number of legacy BIOS compatibility steps it needs to take at the beginning of the boot process means that the code actually in the MBR is only capable of loading one disk block whose LBA number is patched in to the MBR code at the time of installation. That block is usually the first block of GRUB core image. It contains the ...
It has been documented kernel behaviour for many years now that you can not rely on consistent device naming for drives even across reboots on the same server, let alone on different servers.
You will have to write your auto-RAID setup script to detect which drives are in the system and distinguish between the root SSD and the storage JBOD drives.
Before you go any further create (dd) an image of the disk that you can use to restore it if things go badly wrong.
It seems from your post that you have read the TestDisk guide. If not best to read it.
Testdisk should identify the available partition types automatically and the fact that it found an INTEL partition is not a worry. You found ...
If you have a working Linux installation on the PC, you can check if the directory /sys/firmware/efi exists. If it does exist, then your computer has EFI firmware and is not in BIOS compatibility mode. If the directory is missing, then the machine boots using the legacy BIOS.
The partitioning scheme can be checked using fdisk. If fdisk p command ("print the ...
I don't know if it's a rare condition, it's one of the sane ways to use larger disks on older machines. Or when the system firmware is buggy and, e.g., wont properly fall back to a second disk when booting a software RAID setup.
First, you'd check that the machine is not booted with EFI. See “How to know if I'm booting using UEFI?” to check.
If I remove the usb-stick, I get the error " no bootable device found".
Somehow i think the bootloader is not found, if I unplug the usb-stick.
Unfortunately it looks like your thinking is exactly correct.
The first question is: Does the legacy mode BIOS even support booting from the eMMC? If not, then you cannot boot any operating system directly ...
In GPT, a partition cannot be subdivided by partitioning, as MBR required when you had a cap of four first-level partitions on a drive. There's no need, as you can have many more partitions on one drive.
If that pendrive is partitioned with a GPT, erasing the first sector only removes the MBR and the protective DOS style partition table intended for non-GPT aware devices. Those will just throw an error with the protective DOS style partition table and report an unpartitioned device if that data is zeroed.
Linux however is aware of the GPT and ignores the ...
You can use blkid.
Examples with output:
# blkid /dev/sdc
/dev/sdc: PTUUID="92f03b9b-7402-4ad2-8316-08a991c237b3" PTTYPE="gpt"
# blkid -o export /dev/sdc
Or in a script, with the -o value option :
part_type=$(blkid -o value -s PTTYPE $disk)
case $part_type in
gpt) echo "...
Installed OK on the MBR-partitioned drive in this 2010 MacBook Pro A1286 once I
deleted the ext4 partition sda1 which had the entire drive
created a 1MB partition at the front as sda1 for MBR use. Then,
created an ext4 partition sda2 for the rest of the drive for root.
Now, Mint 19.1 install is complete, and I can work on the NVIDIA driver issue, serely ...
Because my system has UEFI firmware and already have a SSD dedicated to Windows my understanding is that I MUST have a UEFI boot partition on my 2nd SSD dedicated to Linux. And if using GPT partitioning in addition it needs to have the 'boot' flag set.
The 'boot' flag is actually the result of gparted trying to present GPT using an interface originally ...