EPM570GF256C5N with incorrect Die?

We have a set of Korean EPM570BF256C5N devices that appear to have the die of an EPM2210 inside... is this an erroneous batch of a set of fake / rebranded chips?

Our previous devices came from Malaysia and were fine.

In fact, recompiling for the 2210 and downloading seems to work...

The devices are labelled:

EPM570BF256C5N

N CAG9M0601A

KOREA

When we try to program these as 256 devices, the JTAG programmer reports:

Expected JTAG ID code 0x020A20DD for device 2, but found JTAG ID code 0x020A40DD

Anyone have any ideas????

many thanks