You don't need a new PCMCIA card to upgrade the current one to the last rev level. It's not hard to do if you have a computer with a card slot.

I use SwapFTL as I found it online for free.

For what it's worth, in theory you can use most any 2 or 4 gig PCMCIA Linear Flash card to operate a system. As long as the pc card you program with can do the voltage level for the write. Most cards read at the correct level for the SX200.

The Main Control writes I believe only to 5V write cards during the remote upgrade process.

One might be able to get a cheap 4M card off of ebay to use as an emergency backup, In theory.