Hi,
about the clock activity it is correct because at call of dev->open within alter_flash_open_dev there is no access to device because there is not a open function defined for epcs.
The ID I'm talking about is the answer to epcs_read_electronic_signature (command# define epcs_res ABh). The ID form my EPCS16 is 0x14, I suppose that yours should be 0x16.
I don't that the option "Disable EPCS id check" could create problem. The electronic signature is answered by device and during initializationthe relative read command is the only one command sent by epcs controller and probably is why your device open fails.
I would investigate about it!
Ciao