> So I connected it to the computer with the USB to NVME M.2 converter

> blkdiscard: /dev/nvme0n1: BLKSECDISCARD ioctl failed: Operation not supported

I've got a USB-to-NVME adapter that exposes the NVME namespaces as SCSI disks. `blkdiscard` did not work with these by default, however it worked fine after I changed the `provisioning_mode` attribute of the disk.

This can be done by identifying the SCSI device ID of the disk (lsscsi) and then changing it with:

    # echo unmap > /sys/class/scsi_disk/a:b:c:d/provisioning_mode

This is absolutely not to be used as an alternative to a real 'sanitize' operation directly sent to the NVME controller. If you actually need to securely erase your data, and the drive dosesn't support the sanitize operation, then you should physically shred the drive and demand a refund from the retailed (goods as sold are not fit for purpose).

Overall, I've found dealing with nvme a frustrating experience. In theory it's nice to have NVME controller firmware be responsible for executing commands from the host (sanitize! change LBA size! underprovision by 30%!) but in practice, it's complete hit or miss whether controllers support a command or will reject it, or maybe they claim to support it but it doesn't work because the controller firmware is buggy shit.

I would like to have raw NAND devices and have the kernel be in charge of everything, but sadly that wouldn't work for Windows so we're stuck in proprietary firmware hell.