I figured out a problem with the Kung Fu Flash Cartridge (FW 1.5)
When starting my game Evil Dungeon 2, the Introtext will be loaded in BASIC from a SEQ File. This works fine from original disk or with the use of an UltimateII+ device, VICE Emulator etc.
It also loads Sprites and other DATA from SEQ file. So I don't know why it has problems with the Intro SEQ files.
Would you like to check if this is a bug?
I can provide you the files to test.