During my "adventures" fixing "The Prayer of the Warrior", i found that the authors discovered a way to use the Z80 interrupt mode 2 without using the correspondant 257 bytes jump table, the problem, this "feature" doesn't work in every CPC.

I'm not going to give now the boring technical details, i have been talking with Executioner and he thinks that it could be useful to get a better understanding if everybody could test the attached files (i have include a DSK and CDTs for easy test) in your CPCs and tell us what colour appears in the border in each test (red, green or anything else) and what CPC model, peripherals you have attached, CRTC type and mainboard version you have (i know that last two things are not easy, but i could make a program that show what CRTC your CPC has).