I have tried it 3 times and it has worked everytime for me. I can't guarantee it for you and obviously it risks permanently bricking you phone. Obviously this is a suggestion and it will be you who bears the risk if it does not work!.

I did as follows:

"flasher -f -F main.bin --erase-user-data=secure -F emmc.bin --erase-mmc=secure" (no quotes)


When this has started, you have 2 options:
1a - either CTRL+Z (Linux) or kill cmd.exe and flasher.exe with Task Manager (WIndows).
1b - Pull out the cable from the phone when the tasks have been killed

or

2 - Just pull out the cable when the phone is zeroising.

After this, turn the phone off and then on. You will get a message saying "Install an Authorised Operating System".

Turn off the phone and run:
""flasher -F main.bin -F emmc.bin -f""

And the phone should accept it and start flashing.

Like I have said, I have done it a few times and not noticed any issues (albeit theoretically it could damage the flash memory) but it may allow you to flash unsigned kernels.