mke18f512 locked out after chip erase

[boguc]

I have series of the factory new mke18f512 chips that i try to program.

Initially, they can be connected to and read with J-Flash:

Read blank output:

However, after erasing the first sector (or attempting to program), J-Link is unable to establish a connection to the MCU:

unlock Kinetis command in j-flash did not helped. Running it on a new, not locked device caused a lock.

What could be the source of my problem?

[boguc · Accepted solution]

Hello, I found the issue. The poor design of the filter circuit for the VDDA supply caused a 1V oscillation on that line. This had an effect of sporadic loss of connection with the MCU. 

Replacing L2 with a 0-ohm resistor fixed the problem.

[PavelM]

Hello, it looks you locket device by writing 11 value into FSEC.SEC register. Kindly check the AN4507 https://www.nxp.com/docs/en/application-note/AN4507.pdf.  Chapter 2.1.1 FSEC register and field settings. Are you able to erase and program device directly from MCUXpresso or IAR or Keil? Did mass erase solved your issue?