[Post-Install] Enlarge EFI partition for dual boot Kubuntu / Windows 11?

[wired2051]

I have a new PC with Windows 11 preinstalled (for gaming). I also installed Kubuntu 25.10 (for productive work). During the installation of Kubuntu, I received a message saying that the EFI partition is only 100 MB in size. The installation program said it had to be at least 300 MB. Nevertheless, the installation of Kubuntu went smoothly and Kubuntu starts and runs without any problems as far as I can see. Windows 11 had to boot and “repair” several times when it was first started after the Kubuntu installation, but now it starts and runs without any problems - as far as I can see. Fastboot is disabled in UEFI and Windows. No relevant data has been stored yet.

Can I continue like this or should I increase the size of the EFI partition? There is plenty of space on the SSD, so 500 MB would not be a problem.

How do I increase the size of the EFI partition?

I have an SSD in my PC, do I need to trim it? Or does this only apply to a new installation / partitioning not to a change in size? I have no experience with TRIM.

I have been using Kubuntu for a long time, but I am not an expert, specially not when it comes to installation. I installed my last PC in 2014 - also dual boot with Kubuntu and Windows - so I need instructions (or a link) that are as simple as possible. My research has been very unsatisfactory and frightening.

[claydoh]

During the installation of Kubuntu, I received a message saying that the EFI partition is only 100 MB in size. The installation program said it had to be at least 300 MB.

Yes, the Calamares folks want there to be a 300mb or larger EFI, but will still move forward with 100. Some distros can put more large files there.
You are fine unless you get into some serious multi-booting, or maybe a lot of distro hopping (leftover boot files for old installs). Most *buntu-like and Debian based ones will not be a problem in this area, currently.

But looking at one of my unused drives, some distros do take up much more boot space. CachyOS (a custom Arch distro) is taking over 140Mb. Windows 11 and *buntu combined are less than 40.

If you ever did need to expand/shrink partitions, you'd need to boot to a live USB and use Gparted or KDE Partition Manager to shrink the (most likely) Windows partition and expand the EFI. I am not sure how well Windows likes this, though. I am sure someone will have more direct experience with this one. I suspect it probably has no problems.

[wired2051]

You are fine unless you get into some serious multi-booting, or maybe a lot of distro hopping (leftover boot files for old installs).

I don't want to do either of those things. So I'll leave everything as it is.

Thank you for your calming response.