sorry, to maybe confusing things about bits and bytes, but i know for sure those 00001000 do only write a value of 0000XXXX. these 00002000 do write values of XXXXYYYY. as for eboot hacks, 1000 codes can also be used that for, but it could also be a memory code in the end, if the address is over the size limit.
you have to look on 2nd row if lies within size. i would say everything whats over 02500000 will be memory code and within this range it can be used for eboot cheats
and just my two cents, but the avp code is a typo i think, but i haven't tried them so far, and master codes were only used for codefreak (3.41 dongle)
i am not any code expert, and i am using
only these action replay codes for years now. maybe skiller should answer about these things, as he is the real codemaster. also he has done the codefreak codetype wip on cmp, as he has friends with codefreak devs.