I removed the installer from the rescue iso, but you can get in back.
In the live system run:
sudo apt updateThen run the advanced installer:
sudo apt install --reinstall sparky-backup-core
sudo sparkylinux-installer guior (text mode):
It doesn't contain grub-efi debs, so can't install grub on uefi machines properly.
Can you try to install minimal iso dev20170202 image?
The advanced installer lets you do that, don't use calamers.