/init is the script in the initramfs, not /sbin/init in your root fs, so it sounds like your initramfs is broken. Try regenerating it with update-initramfs, and attach your /boot/grub/grub.cfg.
/init is the script in the initramfs, not /sbin/init in your root fs, so it sounds like your initramfs is broken. Try regenerating it with update-initramfs, and attach your /boot/grub/ grub.cfg.