Error no such device ubuntu-boot

I am seeing an error being displayed everytime I first program Ubuntu Core image to the solid state drive. The error is the following:

****error: no such device: ubuntu-boot.

I noticed that when I first write the image, the hard drive looks like the following:

After the Ubuntu Core install the hard drive look like the following:

It looks like ubuntu-boot partition is only there after the Ubuntu Core install. Why is the BIOS looking for this partition specifically?