0xFF0F - Interrupt flag, not mentioned in memory layout

[Smileynator]

In the Memory Map, 0xFFFF is explicitly mentioned, but 0xFF0F is not covered.
It seems to fall under "I/O registers" according to the map, but the I/O registers do not list it either.
Only when you go to the specific page about interrupts is it mentioned.

[ISSOtm]

Indeed, seems like it's missing from the "I/O ranges" map. Do you mind opening a PR adding it?

[Smileynator]

I think i can, but currently busy. I will try to do it when i got time.

[ISSOtm]

Fixed by #553.