I have already done a PCMCIA design with the AT89S8252 but this has never happend. It hae 32K RAM and external Flash. The design seems to be like yours. Some CPUs with older mask steppings have problems with the download procedure f.e. but this is new to me).

Is there a chance to get the schematic, this could help a bit to see what you have done.

Under which circumstances does the A15 blow ? describe it a bit more detailed.

Michael