Missing amdgpu firmware blobs since upgrading to kernel 6.15.x

Tried to build linux-firmware from latest commit:

  nixpkgs.overlays = [
    # Override linux-firmware
    (self: super: {
      linux-firmware = super.linux-firmware.overrideAttrs ( old: rec {
        version = "20250613-1d98972a56356ccd3193cb6f1a74a4e71d8c4e37";
        src = pkgs.fetchgit rec {
          url = "https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git";
          rev = "1d98972a56356ccd3193cb6f1a74a4e71d8c4e37";
          hash = "sha256-WFBA4vPfV3ivKcXuEP9Gol0qBnY4oqGfKmslqxEr7Dc=";
        };
      });
    })
  ];

still getting it, and blob still does not exist (nor does it in upstream repo).