I haven't seen this issue here so I thought I'd point it out to others. Or, it's possible I'm just an idiot and no one has done this. I installed a LCD DMD in TSPP a couple of days ago. When I first booted the machine the display was showing white, which is default for the SIGMA ROM. I was unfamiliar with the buttons and menus, and began scrolling through the different colors having a look. I had it on red and hit save by mistake. I wasn't too worried about it as I was going to download the TSPP ROM and that ROM would overwrite the SIGMA file right? Wrong. I loaded TSPP and boom, I have color. I started playing and it didn't take long to notice the yellow was not true yellow. There was a greenish tint to everything yellow. Of course, Simpson's characters are yellow, and Homer, Bart, everyone displayed looked sick and about to puke with this greenish tint. I got my wife and she agreed yes, something looks off.
So today, I thought maybe selecting the red has caused the issue. I downloaded the SIGMA file and installed it. The display was showing everything in red. I was really surprised, as this means the red color selection is saved somewhere on the board. I fully expected the default white to be showing. I went ahead and switched to white and saved. I loaded the TSPP ROM and now I have bright yellows with no green tint. It sure appears that a color selection saved in SIGMA will impact game ROM color displays. I don't understand how, since if the red was stored somehow within the board I would expect the yellow to have an orangish tint instead of green if the colors were somehow mixing. When I first saved the red my initial thought was I better switch it back to white. My second thought was why bother, the file will be overwritten. With as many color DMD's out there now I'm wondering if there's others that have done this and don't know that their display is not showing the proper colors. Perhaps the color DMD folks can advise as well.
Hope this helps someone