You need to do it manually step by step.

• Windows10: Free Minitool Partition wizard refuses to do it, unless you buy a pro version.
• Linux: gparted complains; "GNU Parted cannot resize this partition to this size. We're working on it!" It rarely succeeds. It only occasionally somehow succeeds.

Our solution is

1. make a backup of contents of EFI partition.
2. delete the EFI partition.
3. re-create it with the extended size.
4. copy the contents to the new EFI partition.

Step by step guide. You need root priviledge or sudo.

1. # mount /dev/sda1 /media/ubuntu/XXXX # Use gnome-disks GUI. XXXX depends on your system.
2. # mkdir esp/
3. # rsync -av /media/ubuntu/XXXX esp/ # make a backup of the contents.
4. # sudo umount /media/ubuntu/XXXX
5. # sudo gdisk /dev/sda
   1. p # list of partition
   2. d # delete the partition.
   3. 1 # select the first partition.
   4. n # new partition.
   5. 1 # the number of new partition
   6. Enter # default 2048 sector.
   7. Enter # default X-th sector depending on the size of partition.
   8. EF00 # Hex Code for a EFI system partition.
   9. w # write the operation you have done.
   10. Y # final comfirmation.
6. # sudo partprobe /dev/sda # ???
7. # sudo mkfs.fat -F32 /dev/sda1 # format the EFI partition as FAT32.
8. mount /dev/sda1 /mnt/
9. rsync -av esp/ /mnt
10. If it is a Linux drive, modify the UUID on /etc/fstab
    1. blkid | grep EFI
    2. nano /etc/fstab.