Brewpot cover on

So i've had a Belgian Trippel in my primary for about 3 weeks now and everything seems fine, but one thing i keep worrying about is the fact that I kept the brewpot lid mostly on while i was boiling it. The reason for this was I overestimated the stove's potential for maintaining a boil, so the only way i COULD maintain it was to cover it.

I'm just wondering what negative effects this could have on my beer, since a few people have told me to avoid covering the wort while its boiling.

It could have some a DMS (creamed corn) odor, especially if you used pilsner malt. I've had this once in the past. Luckily I had just started kegging, so I was able to strip out the DMS by bubbling CO2 through the keg. I think I learned that from Revvy.

The biggest reason for a rolling boil in an uncovered kettle is to remove diacetyl.