How to boot your operating system if you destroy the MBR (Win/Linux)

Oh dear, your server will not boot, you have done something and destroyed the master boot record or grub boot loader or something similar to that!

What you really want is just to get the Operating system booted, you have been on google and found 101 identical guides telling you how to reinstall your MBR or repair or reinstall grub but none of that works or you have no time to waste, you just want your server running ASAP and you will deal with the issues later! There is a fairly simple solution that will work in most cases as long as it really is only the MBR or grub boot loader you have damaged/deleted.

When it is time to reinstall grub then do check out our other guide on doing so: Recovering from a damaged grub install

Step 1 #

You will need IPMI access to your server, if you do not have this then please open a support ticket requesting it.

Step 2 #

Download a supergrubdisk 2 ISO file from here: https://www.supergrubdisk.org/wizard-step-download-super-grub2-disk/

Step 3 #

Load the Java virtual console using your IPMI (we have a guide on that if you get stuck: How to access your IPMI)

Step 4 #

Within the virtual console click on the virtual media tab and select ISO file and pick your fresh Supergrubdisk 2 ISO you downloaded in step 2.

Step 5 #

Reboot the server, using macro ‘ctrl+alt+del’ or power control > power cycle within the java console, at the appropriate time, usually after the second manufacturer logo flashes on the screen press F11 to get the boot options menu and select the UEFI ATEN CD-ROM or similar.

Step 6 #

Allow the ISO to boot, depending on how far away you are from your server this may take some time (5 – 10 minutes), eventually, you will be presented with a simple options screen, select ‘Detect Any Operating System’ This will scan all attached disks for any trace of an operating system, if you have a /boot directory (Linux) or a C: partition (Windows) then it will probably find it and give you a list of the operating systems it found, select the one that looks right and it will boot your OS for you without any MBR or grub installation.

NOTES #

1. This will not fix your boot issues, this is a 1-time thing, every time you want to boot your server you will have to do this until you fix the actual issue.
2. If you use mdadm raid or LVM you will see the options to enable this functionality in the initial menu first before running the ‘Detect Any Operating System’ option