Create a bootable Knoppix Linux USB drive using Etcher (Mac/Windows/Linux). Option Boot the Knoppix USB drive and select the orange icon labeled "EFI". Open a terminal app (the black icon on the bottom left of the Taskbar near the "Start" menu).
Run the following command to get the drive ID for your Crucial SSD or you can use the GSmartControl app which is located "Start Menu --> System Tools --> GSmartControl" to get the drive ID.
sudo lsblk -o NAME,FSTYPE,LABEL,SIZE,MODEL
To confirm you are using the correct drive identifier, run this command making sure to substitute the correct drive identifier for the SSD in place of the "sdX" in the following command which should show you the Crucial MX100:
sudo hdparm -I /dev/sdX | grep -i model
To use the ATA Secure Erase feature built into the SSD you must issue the following two commands replacing the "sdX" with the correct drive identifier for the SSD. The first command enables the ATA Security feature and the second one initiates the hardware secure erase which can take anywhere from 20 seconds to several minutes. The security lock will be disabled upon successful completion of the secure erase.
sudo hdparm --user-master u --security-set-pass Eins /dev/sdX
sudo hdparm --user-master u --security-erase Eins /dev/sdX
If the secure erase does not complete successfully, then the drive will become locked on the next power cycle. If the secure erase does not complete successfully you can remove the security lock with the following command:
sudo hdparm --user-master u --security-disable Eins /dev/sdX
Besides erasing the SSD, the hardware secure erase will also reset the SSD to factory defaults which can sometimes get an SSD out of a weird state.
This procedure is best performed while the SSD is connected to an internal SATA controller or to an external e-SATA port. Doing this over USB is risky since some USB Adapters, docks, enclosures may interfere when the SSD goes offline leaving the drive permanently damaged. I have successfully performed this procedure over USB using a Crucial USB to SATA Adapter.
