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I have been reading for some time now, and have some ideas, but don't want to lose all my data.

I was doing an update, and found that I didn't have enough space left in my /dev/sda2 partition. I think it was my 'boot' partition for Ubuntu.

I opened up GParted, and shrunk SDA1 and Moved, and Grew SDA2 Partition.

After I finalized the disk, then GParted said I might have an issue with booting.

I am now unable to have my BIOS see the OS, and my system will no longer boot.

I tried attempting to re-write my MBR and GPT tables with a livecd, but either I don't know what I'm doing, or I'm doing it wrong.

I saw there might be a way to do a grub-update and possibly fix the MBR....

Zanna
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CalicoBrak
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2 Answers2

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Your disk is an MBR disk with BIOS-mode boot code but it also has an EFI System Partition (ESP) with EFI-mode boot loader files on it. This is an unusual combination, and it's not clear if your computer had been booting in BIOS/CSM/legacy mode or in EFI/UEFI mode. This fact makes it difficult to advise you on how to repair the boot loader, since a repair procedure based on the assumption of a previous BIOS-mode installation might fail if the computer had actually been booting in EFI mode and vice-versa. It's also not clear how old your computer is or what brand and age of firmware it has -- some EFIs (especially older ones) are buggy and might work poorly when booting in EFI mode. This is especially true when an MBR disk is at play.

My own inclination, based on the limited information I have, would be to use my own GPT fdisk (gdisk) to convert the disk from MBR to GPT form. It will then be possible to install an EFI-mode boot loader on the computer -- you can either use Boot Repair (from an Ubuntu recovery tool booted in EFI mode) to (re-)install the EFI-mode version of GRUB or boot with the USB flash drive version of my rEFInd boot manager and install it permanently via a Debian package or PPA.

OTOH, if your computer has a buggy enough EFI, going with a BIOS-mode boot loader may be more reliable. If this is the case, you shouldn't mess with the partition table. Instead, you should learn how to control your computer's boot mode and boot an emergency Ubuntu system in BIOS mode. You can then run Boot Repair. With any luck that will set up a consistent BIOS-mode GRUB, which will then boot the computer.

You can test whether you've booted Ubuntu in BIOS mode or in EFI mode by looking for a directory called /sys/firmware/efi. If that directory is present, you've booted in EFI mode; but if it's absent, you've booted in BIOS mode. Controlling the boot mode can be tricky and how to do it varies from one computer to another. See my page on the CSM for some information on this topic, but be aware that you'll probably have to poke around in your firmware and your computer's built-in boot manager to figure it out for your specific computer.

Rod Smith
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Although I have gpt, usually automatic boot-repair 3-step solution on Ubuntu live-usb works for me and makes my system bootable again.

link: https://help.ubuntu.com/community/Boot-Repair

2th option.

bogec
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