paulb_nl on the Shmups forums has released his own custom firmware for the OSSC that ads special modes to help with Game Boy Interface Compatibility. Here are some options:
- Line2x 240×360 and Line3x 240×360 are added to 384p Proc menu.
- Line2x 240×360 outputs 1200×720 with default settings.
- Use these settings for 1280×720: H.active 256, H backporch: 24, Hsynclen: 18.
https://shmups.system11.org/viewtopic.php?p=1322960#p1322960
https://drive.google.com/file/d/1Q45CWw7po8alJOxtoTzrb9TrZW_0n01l/view?usp=sharing
