Reading/writing sectors using default keys...

I have Proxmark along with a new MIFARE card presumably set with one of the default keys.  I'd like to read and write sectors using those keys, however it looks like ReaderMifare stops processing after the auth-A (0x60) command (tag nonce is received, but mf_nr_ar is simply set to zeros).  I am able to successfully get anticollision traces from ReaderIso14443a, but of course things don't proceed further.  Am I just missing something?  It seems like I would need to implement the LFSR and associated filter functions to generate the key streams to proceed past authentication.

Also, is ks_list supposed to contain extracted ks1 and ks2 after calling ReaderMifare?

Thanks.

- Eric