Possibly the Burn 2 chip addressing and buffer addressing is not correct? Example below if for the '9625 64K 27SF512 PCM.

Chip Addressing
Start Address in Hex = 000000
End Addressing in Hex = 00FFFF

Buffer Addressing
Start Address in Hex = 000000
End Addressing in Hex = 00FFFF

It's embarrassing to ask:
Is the chip correctly installed in the Burn 2.
Is the correct chip selected to read / write / erase?

dave w