Custom ISO with initrd.systemd enabled gives me: "failed to setup loop device for /iso/nix-store.."

The image shows what happens when i boot on the ISO, i get the error:

x sysroot-nix-rrv\v2dstore.mount - /sysroot/nix/.rc-store
    Loaded: loaded (/nix/store/1779scwag89fja51b1q7jg5savcj5tyrlnltrd-fstab; generated)
    Active: failed (Result: exit-code) since Tue 2023-07-29 18:37:53 UTC; 35s ago
Invocation: 94ea87636cc24a4c83d8e147275a8124
    Where: /sysroot/nix/.rc-store
    What: /iso/nix-store.squashfs
    Docs: man:fstab(f)
    man:systemd-fstab-generator(8)
    Item peak: 1.9M
    CPU: 9ms
Jul 29 19:37:53 hostruc systemdf11: Mounting /sysroot/nix/.rc-store...
Jul 29 19:37:53 hostruc mountt2531: mount: /sysroot/nix/.rc-store: failed to setup loop device for /iso/nix-store.squashfs.
Jul 29 19:37:53 hostruc systemdf11: sysroot-nix-rrv\v2dstore.mount: Mount process exited, code-exited, status=82/n/a
Jul 29 19:37:53 hostruc systemdf11: sysroot-nix-rrv\v2dstore.mount: Failed with result: exit-code .
Jul 29 19:37:53 hostruc systemdf11: Failed to mount /sysroot/nix/.rc-store.

and I am pretty confident this is because I have initrd systemd on a iso build, so does anyone know how I can fix this issue in either my flake where i set how the iso is built or in main.nix (which i linked), which is about initrd settings
main.nix (imported in configuration.nix):

flake.nix:

Image:


(it fails during the initrd phase)

I had to add the pr
github:NixOS/nixpkgs/pull/291750
as a input, so like:
nixpkgs.url = "github:NixOS/nixpkgs/pull/291750/head";
So i’ll have to do that until its merged.