Occasionally, when using a segger to connect to a K64FN1M0VLL12, the segger reports a failure to connect. We tried a number of things. Finally, we connected to the K64 over the EzPort. The Read Status Register reports 0x80 (somehow the flash security bit is set, but bulk erase is not disabled). Following some suggestions on the discussion boards, we tried issuing a Write Erase (status changes to 0x82, which is expected), and then a Bulk Erase. Status changes to 0x83, but the write never completes.
Is there anything else that would prevent a Bulk Erase command from working?