Tetris always brings up the same block

[maxbit89]

Hy we used gameboy.js for a little demo and wanted to run Tetris. But Tetris always gives the square Block. ^^

[juchi]

Hi,
I am aware of this bug but was never able to track it down. Probably due to an error of implementation of one of the instructions or hardware (maybe the timer), but I don't know what.
Would be happy to merge a fix if someone finds the error

[maxbit89]

I didn't spent time understanding what is going on. But my first idea was that this could be some kind of Copy Protection. I remember on the NES they tried to write on a memory location where they know that it didn't exist (ROM and RAM are located inside the Game Cartridge), and read it back. If the Value was equal to the written Value they knew some thing isn't right.