LIBRETRO: ZVISION: Zork Nemesis crashes in ScummVM 2026.2.1git with Graphics::Surface::copyRectToSurface assertion

[jordanbartee]

I wasn't sure where to post this, as it effects the libretro core ONLY. The same game and data directory launch correctly in standalone ScummVM 2026.3.0. The crash occurs only in the libretro ScummVM core (2026.2.1git). I hope this is the right place to file this ticket, as the libretro github explicitly bans filing core and game bugs, but a mere mortal like me has no way of knowing who actually mantains the ScummVM core.

Core version: ScummVM 2026.2.1git (RetroArch)
Platform: Steam Deck OLED / SteamOS
Game: Zork Nemesis (DOS)

Steps to reproduce

Install ScummVM core system files (themes/extras).
Add a fresh Zork Nemesis installation built from the original CDs following correct Scumm directory structure.
Launch the game.

Expected:

The game launches normally.

Actual:

RetroArch exits completely.

Launching RetroArch from a terminal produces:

User picked target 'znemesis' (engine ID 'zvision', game ID 'znemesis')...

retroarch:
/builds/libretro/scummvm/backends/platform/libretro/../../../graphics/surface.cpp:261:
void Graphics::Surface::copyRectToSurface(...):
Assertion `height > 0 && destY + height <= h' failed.

Control:
The identical game directory launches successfully in standalone ScummVM 2026.3.0 with the same options and data files.