It depends. You need to check what you wrote with your ColdFire image to the flash protection area (around 0x410), see https://mcuoneclipse.com/2012/11/04/how-not-to-secure-my-microcontroller/ .
If you still have flash mass erase enabled, you are ok. Otherwise you need to replace the device.
If are still able to erase, it could be that the device is constantly resetting. PEMicro has a Kinetis Recovery tool which you can use in this case. I believe you can find it on their web site, and this tool recovered many Kinetis devices for me. It constantly tries to connect to the device, and usually after several seconds I'm able to get control over it.
I hope this helps,
Erich