Unable to install manjaro from cli: [basepkgs255], not enough free space

Hi, first post here.
I was planning to install a gnome-majaro system on a small netbook, using ZFS with compression and dedup to increase the usable disk space.

I partitioned the internal drive in
255MB fat32 efi partition
28GB for / in ZFS
512MB swap

The configuration went smotly until I tried to install Gnome: it downloads the required packages, however when it checks available space it aborts the installation with [basepkg255], claiming there are less free blocks than required. The problem is that by inspecting the filesystem with df there are still 26GB of space left, even during the package install and download.

Any help for an arch/manjaro newbie?

maybe do partitions before launching installer

I already partitioned the disk, in fat32, ZFS and linux-swap respectively