|0000 - 0FFF||4 KB RAM (or when 32 KB RAM is used until 7FFF)|
|8000 - 81FF||Build in system ROM|
During start-up the system ROM is also mapped to address 0000. The ROM will be swapped for RAM after the first OUT 4 instruction. RAM is mirrored between address @0000-@7FFF depending on the RAM size. So for a 4 KB RAM system the RAM on address @0000-@0FFF is mirrored 8 times at @0000, @1000, @2000 etc.