Referring to page http://highlowtech.org/?p=1695, is it possible to program ATtiny84A as well, or just the chip version ATtiny84 (without "A")? Does anybody know?
According to the PDF ATTiny24/44/84 to ATTiny24A/44A/84A Migration AppNote it should be pretty easy as there are only some differences in electrical specifications. No changes in registers or so.
The signature bytes are the same too, so it should be posible even without adding another boards.