Yes it is easily possible to change /boot/efi with Agama and Leap 16.0 to any size you want. It does not take much and can be found by playing a little bit with Agama…you can’t destroy anything until you have fully configured all necessary installation steps (software, user, passwords, …) and hit install.
Following an example how to create 4 GiB /boot/efi partition.
First delete the initial disk layout proposal:
Now click add a new partition:
Type
/boot/efi as mountpoint. Use FAT and 4 GiB. Uncheck growing:
Add another partition for / with btrfs and automatic growing and snapshot(and swap if required or wanted) The final disk layout will look smth like this (without swap for this example):
