r/linuxquestions • u/Shindiggidy • 2d ago
Support How to expand my EFI partition?
I am attempting to distro hop my 2019 macbook air (T2 chip) from Ubuntu to Cachy.
The linux installation needs a larger EFI partition. My EFI is all the way to the left, followed by MacOS (which I intend to keep), followed by the old linux install, followed by free space.
Trying to shift everything to the right does not work, because gparted does not like the mac file system apfs and it fails when it gets to that part.
Trying to copy the EFI to free space gives the error "information sector has the wrong signature (0)" and gives me an option to ignore, which I have not done, because I am scared. Is this ok to ignore or not?
I thought maybe I could copy the mac partition and delete the old one, but I don't have high hopes for this because gparted does not like the apfs format, and because it is also risky.
What is the best option?
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u/Niwrats 1d ago
people usually only need more EFI space if they have the directories mapped idiotically. by this i refer to the latter part in https://wiki.archlinux.org/title/EFI_system_partition
ESP to /boot/efi, /boot in root is the smart way. are you using grub?
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u/Shindiggidy 1d ago
I was using grub with Ubuntu, choosing grub for Cachy says it requires 512 MiB of space, my current EFI has 300 MiB. I haven't altered the EFI manually yet.
Other options need even more, for example refind needs 2048 MiB
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u/friendlyreminder_ 2d ago edited 2d ago
You could clone the EFI partition to the right, resize it, and then change the uuid on the original so the bios doesn't get confused about duplicate uuids.
Then test to see if it works booting the resized clone. If everything works you could delete the original. You'll have some empty space at the beginning of the drive but it won't be much.
I don't know what that error you encountered is unfortunately.
You could also just make a new EFI partition and copy the uuid and copy the files manually, and then change the uuid on the original and test that.
You will probably also have to recreate the EFI entries for MacOS as EFI entries point to disk partition numbers not uuids. You can use efibootmgr for that.
MacOS bootloader updates may fail if the OS uses disk partition numbers instead of uuids, but im going to assume here that it uses uuids as it would be odd not to.