Need some advice

I got my Mega ED the other day in the mail and had added afew rom's to test it out. Two of these were Shadow of the Beast and The Immortal. Both worked just fine last night so off to bed I went. I added a few more rom's this afternoon and when I went to try them, a good portion work just fine but neither of these work at all, just go to a black screen and lock up the cart.
Oddly enough this seems to happen with any EA game I have loaded on the system today (SotB 1 and 2, the Strike series, Immortal, Polterguy, Fatal Rewind) though it also seems to happen with Devilish.

My question is this basically, Why did it work last night but now it won't? I don't rememeber changing anything in the system is there some sort of hard reset I can do that might alleviate the problem?

I've already tried sourcing different files and reformatting the card
Any help would be greatly appreciated

EDIT: I should have also stated that I'm using a model 1 HDG non TMSS to test

 

Nevermind
I figured it out, had to disable in-game menu to make them work. :cool-new:

 

I wonder, how do those in-game menus work? Sounds like a supervisor, but how does such a thing even work on the Genesis's limited resources?

(I take that back, in this case, it DIDN'T....)

 

OS modify vblank interrupt routine, and put small piece of code in ROM to be able to call in-game menu

 

Interesting I guess it interferes with some part of the code that the games use to boot up.

As an aside, I would like to personally say what an awesome piece of tech the everdrive really is Krikzz. Very nice work sir!

 

vblank modification is change a timings a bit, most games don't care about that, but some games dislike it. also it may create some problems for joypad. so, compatibility going down if ingame menu was activated

 

oh yes, the MEGA Everdrive is trully a great product, well worth the money if someone can spare them compared to the normal version...