480p x2: No
Tested consoles (all NTSC):
PC Engine Duo R (usually needs analog sync LPF)
PS2 (both PS2 and PS1 games)
Xbox (1080i didn’t work)
No GBI ULL, but GBI LL still works.
3x and 480p 2x will display if converted for the VGA port, but the image is squashed and parts of the screen are noticeably wavy that I couldn’t resolve.