wrflash and centennial 16MB flash

I have a Centennial/Nortel 16MB flash at work, which I'm trying to
read and rewrite using Linux 2.2.25 and pcmcia-cs 3.1.33.  Reading
using /dev/mem0c0c seems to work.  Writing using wrflash from openap
or dd does not.  Ie:

# wrflash -i -e /dev/mem0c0c </dev/zero 
Partition size = 16 mb, erase unit size = 128 kb, start address 0x0


erasing block 1 of 128 (0x0-0x1FFFF)
block erase failed: Input/output error
---> failure.


cardctl ident says:

Socket 0:
  product info: "3Com Corporation", "3C589", "TP/BNC LAN Card
  Ver. 2a", "000002"
  manfid: 0x0101, 0x0589
  function: 6 (network)
Socket 1:
  product info: "Centennial Technologies, Inc.", "FL16M-20-11119", "16 MEG FLASH w/16 Mbit AMD devices", ""


>From dump_cis (skipping socket 0):

Socket 1:
  dev_info
    FLASH 200ns, 16mb
  common_jedec 0x01 0xad
  common_geometry
    width 2 erase 0x10000 read 0x1 write 0x1 partition 0x1 interleave 0x1
  vers_1 4.1, "Centennial Technologies, Inc.", "FL16M-20-11119",
    "16 MEG FLASH w/16 Mbit AMD devices", ""

Inserting the card causes these modules to load:

memory_cs               9152   0  (unused)
sram_mtd                3296   0  (unused)


Output of cardmgr -V:
cardmgr version 3.2.2

Could someone clue me in on what I'm doing wrong?

Thanks!

- Morty