RAM is from 0x0000 to 0x7fff. Between 0x2000 and 0x7fff the RAM is "shared" with program space. Below 0x2000 the program is burned into the 8052 chip itself and cannot be changed. You should be able to access (and program) RAM there, but you cannot run programs below 0x2000. From 0x8000 to 0xf7ff is EEPROM.

If you try to "erase" RAM it is not likely to work, since RAM does not need a special "erasing" procedure. So I'm not surprised you got an error doing that. But I don't know why you are unable to program at 0x2000. That should work. Are you using a pre-assembled board? It it brand new?

Frank Kienast