I might have solved this 4 year old (more?) problem.
I have a very old programming manual. It's been in my posession for years. It is really a xerox of a book, which was stapled together using carpet staples on the end.
From the previous posts, I gathered that setting CGA flags was correct.
On the very first page, (first one before got ripped off), it showed BASICA code to set the active graphics card between Monochrome Adaptor, and a CGA Adaptor in the computer at the same time.
I re-wrote the code in a QBasic wrapper, added my contact info as a 4 second msg, and compiled it into a single EXE. CMPOSITE.EXE
I tinkered with DOSBOX a bit, and it did indeed set the composite mode of the CGA (CGA video mode set of course) emulation.
Will it remain on in between various accesses of programs and other such processes? That depends.
I did a test of a CGA based Turbo Pascal program I wrote to see if the composite setting carried over. It did not. Maybe it's the way my program operates.
But, it did seem to work when running under BASICA at screen 1 & screen 2. (320x200x4) & (640x200x2) which are the composite modes of course.
This is obviously only a temporary fix, but MAYBE, it will work for your game(s).
I would love to see a list of which games this gets the composite flag working again on.
Love to chat about how I did composite CGA video graphics with my Tandy 1000HX, but I'm sure you guys wanna see the program I wrote.
Enjoy! Remember, this is only a homebrew patch that may or may not work.
BTW.. Try at your own risk. It only sets 2 low memory address values, so it won't even hurt a fly as far as I'm concerned.
If it ain't borked, fix it 7 times.. Reinvent the wheel every day. Compile 8085/8086 code daily. Drink lots of instant coffee. Look both ways before cooking a turkey.