Cross compiling fails with among others 'Cannot allocate memory'

I’m trying to get nixos onto a pinenote, an aarch64 device from pine64.

 > nix --version
nix (Lix, like Nix) 2.93.4
System type: x86_64-linux
Additional system types: aarch64-linux, i686-linux
Features: gc, signed-caches
System configuration file: /etc/nix/nix.conf
User configuration files: /home/ton/.config/nix/nix.conf:/etc/xdg/nix/nix.conf:/home/ton/.nix-profile/etc/xdg/nix/nix.conf:/nix/profile/etc/xdg/nix/nix.conf:/home/ton/.local/state/nix/profile/etc/xdg/nix/nix.conf:/etc/profiles/per-user/ton/etc/xdg/nix/nix.conf:/nix/var/nix/profiles/default/etc/xdg/nix/nix.conf:/run/current-system/sw/etc/xdg/nix/nix.conf
Store directory: /nix/store
State directory: /nix/var/nix
Data directory: /nix/store/04fzclc8sa1ziv056i3ljnj9qy5kabay-lix-2.93.4/share

Here’s the command and output: https://bpa.st/VFFA.

And here is the repo I’m building from (I’ve made no modfications yet): GitHub - WeraPea/pinenote-nixos: NixOS Module and Packages for PineNote · GitHub

Any help or pointers are much appreciated.