RetroTINK 4K firmware v1.21.0 adds user-defined modelines via SD card

Mike Chi released experimental firmware v1.21.0 for both RetroTINK 4K models today, and the headline feature is modeline management via the SD card. Previously, the RT4K allowed four custom modeline slots. The new firmware makes slots 3 and 4 user-definable, letting you load a modeline file directly from a /modelines folder on the SD card and match it to a profile. No more overwriting saved slots every time you need a different output configuration.

This matters because modelines control exactly how the scaler outputs to your display: resolution, refresh rate, sync parameters, and the rest. Power users running multiple setups or profile packs have been working around the four-slot limit for a while. The ability to store named modeline files on the card and call them from a profile is the kind of workflow fix that sounds minor and saves real time.

The firmware is marked experimental. RetroRGB has published a VHS profile pack alongside it that includes a set of tested modelines for use with the new feature. If you own a RetroTINK 4K CE or Pro and use custom profiles, this is worth installing. Download via the experimental firmware page at the RetroTINK firmware repository.