Check your /boot/grub/grub.cfg to make sure you have an initrd path. This thread shows what mine looked like setting up dual-boot with Ubuntu
Make sure to make a backup copy of your boot/grub before you change it so you can roll back if things go wrong. Also if you follow the instructions I left there, replace vmlinuz-4.18.0-15-generic with the name of the kernel that didn’t get built.
Good luck!