月份: 2021 年 8 月

The Issue

We want to convert our Ubuntu 20.04.1 LTS installation from BIOS to UEFI

Note

Before starting, we have to make sure that we have enough free disk space on the system disk (at least 1G, minimum 550MB probably will do as well)

There are many ways to

The Fix

1 Make sure the current hardware support both BIOS & UEFI, and the current Ubuntu installation is BIOS

Warning!!!: Before continuing, we must make sure that we have a full disk backup, although usually this type of conversion should not cause data loss, but there are still chances that data can get corrupted, so full disk backup is necessary.

2 Follow How to Convert Ubuntu 20.04.1 LTS OS disk from MBR to GPT/GPT to MBR without losing data to convert the disk first

(MBR with extent should not be an issue and should be able to be converted to GPT successfully)

Note 1: For this guide, we assume the disk we are converting is the only disk on the system, which means it is used for storing the operating system and user data

Note 2: For this guide, boot-repair-disk is preferred over Ubuntu Desktop Live (Although, we can use Ubuntu Desktop Live then install boot-repair on the live system too)

3 Boot from boot-repair-disk again

4 Launch GParted

5 Assume we only have one partition on the disk which is used for operating system itself and user data, we resize the partition then move the block with data to the end of the slide, so that we can have 550MB unallocated space at the beginning of the disk

6 Make sure the disk (partitions are unmounted first)

Click on Resize/Move button, Click on OK button on the warning screen, Click on the green Check button to commit the changes

7 Right Click on the unallocated space at the beginning, Click on New

8 For File system, Select Fat32, For Partition name, we enter EFI System Partition, Click on + Add button

9 Click on the green Check button to commit the changes

10 Right click on the fat32 partition that we have just created, Click on Manage Flags, Click on boot (boot and esp should be checked), Click on X Close button

11 Restart the system (Boot into BIOS/UEFI)

12 Change the settings to UEFI from BIOS

13 Boot from Boot Repair USB again

14 Click on No button if asked for updating the software

15 Click on the first button “Recommended repair (repairs most frequent problems)“

16 Carefully following the steps required by the Boot Repair software

17 When the boot repair is done without error, we need to restart the system (Remember to remove the bootable USB)

18 Now we should be able to boot into Ubuntu via UEFI

1 Download Ubuntu Desktop Live or boot-repair-disk

2 Create a bootable USB from the downloaded iso file using balenaEtcher or Ventoy suggested, refer to the following guides if necessary

List of free software/programs/Utilities to write ISO files to USB HDD/Thumb Drive/Flash Drive (Create bootable USB drives) easily etc. (balenaEtcher)

Another Simple and open source Multiboot USB creation tool (Ventoy)

3 Configure the BIOS/UEFI from the system which we want to convert the disk, so that we can boot it from USB (Refer to the motherboard manual or Search the motherboard model if necessary)

(If Boot Repair is asking to update the software, click on Nobutton)

4 Launch the terminal from the live system

5 We use the following command to convert the disk from MBR to GPT
(If gdisk is not installed, use sudo apt install gdisk to install it first)

sudo apt gdisk /dev/sdx

Note: Replace /dev/sdx with the correct disk label e.g. /dev/sda, /dev/sdb etc.

Output

GPT fdisk (gdisk) version 1.0.5
Partition table scan:
MBR: MBR only
BSD: not present
APM: not present
GPT: not present
***************************************************************
Found invalid GPT and valid MBR; converting MBR to GPT format
in memory. THIS OPERATION IS POTENTIALLY DESTRUCTIVE! Exit by
typing 'q' if you don't want to convert your MBR partitions
to GPT format!
***************************************************************
Command (? for help):

MBR to GPT

Enter w to convert MBR to GPT partition
Enter y to confirm and write the change

GPT to MBR

Enter r to enter the recover and transformation
Enter g to convert GPT to MBR partition

We can enter p to check the partitions.

Warning: We will lose our bootloader like grub, which means we will have to reinstall/fix the bootloader/grub etc. after the conversion, we can use boot-repair-disk from Step 1 to fix it easily by following steps prompted by the software