On 25 Jul, 21:43, Chris wrote:
Of course they can - incorrect data downloaded to cards can easily
makethem inoperable.

I've not yet come across r/w memory that can't be reset if theres
dodgy data on it so unless they're upgrading any software there may be
on it I can't see how it could happen. And if thats the case you have
to ask yourself why.

Both today anda couple of weeks ago are being put
down to Transys.& no hacking fix.#

Yes , because I'm sure TfL would release a statement saying "transys
have been attempting a workaround for the MiFARE hack but have so far
failed miserably".

B2003