You can create a new folder named CERTIFICATE, it can be empty, as it was before.
Then use Image burn to create the .ISO & .MDS files. The CERTIFICATE folder has
no purpose in these projects but some Apps & players expect it to be there.
If I remember correctly 2.6 had the same issue and this is what I did.
This was excellent help! I’m new to this and this was exactly what I needed.
Your assistance was VERY MUCH appreciated!