The grub installation failed

[Gonçalo Saúde Ribeiro]

Grub installation fails reported as fatal error.
I was trying to install Ubuntu 20.04 on my ASUS X555LD-XO334H with Windows 10 installed.
I've created a 70GB clean partition on windows.
Then, I've started from a live USB and did all the steps for install.
On the partition steps, I've created a 2GB ext4 /root partition, then a 4GB swap and the remaining with /.
When I tried to go to next step showed an advise that no EFI partition was created.
I went back, clean the last partition, create a new one, as EFI with 256MB.
Then, I created a ext4 as / with the remaining space.
With that I was able to go to next step, the Time-zone.
After a while I received the message.
The report went automatically to you.

Thanks in advance

ProblemType: Bug
DistroRelease: Ubuntu 20.04
Package: ubiquity 20.04.15.2
ProcVersionSignature: Ubuntu 5.4.0-42.46-generic 5.4.44
Uname: Linux 5.4.0-42-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.11-0ubuntu27.4
Architecture: amd64
CasperMD5CheckResult: pass
CasperVersion: 1.445.1
Date: Sat Nov 28 17:53:01 2020
InstallCmdLine: BOOT_IMAGE=/casper/vmlinuz file=/cdrom/preseed/ubuntu.seed maybe-ubiquity quiet splash ---
LiveMediaBuild: Ubuntu 20.04.1 LTS "Focal Fossa" - Release amd64 (20200731)
SourcePackage: grub-installer
UpgradeStatus: No upgrade log present (probably fresh install)