Bragging about previous funded PhD position to acquire another?
This is just an opinion:

You will need to be very clear why you left, and you cannot leave room for the suggestion that it was just because things got a bit uninteresting. The way you have described it in your question leaves me with that presumption, and on that basis I would feel uncomfortable with working with you on a fixed term (or fixed goal) project such as a PhD.

i.e., the obvious question in the mind of the reader of your CV will be, "How do I know you won't disappear on me as soon as things get a bit boring or difficult?"

Frankly, I think you have more to lose than you have to gain by discussing it.