Secure disk wipe with Windows format command

From Windows 8 Microsoft snuck in a refinement to the format command. It is now possible to get it to do multi-pass random-number disk wipes. From the help (Win 10 20H2):

 /P:count  Zero every sector on the volume. After that, the volume
           will be overwritten "count" times using a different
           random number each time. If "count" is zero, no additional
           overwrites are made after zeroing every sector. This switch
           is ignored when /Q is specified.

So to do a single-pass random wipe:

  • Repartition disk with one partition (if desired) and give it a drive letter (let’s say F for this example). Probably a good idea to remove any OEM, EFI, recovery partitions like this. A quick way to do this is to use the clean command in diskpart.
  • Run format F: /P:1
  • If you feel like it finish up with a clean command in diskpart.

This should do a pass with all zeros, and then a random-number pass.

Note this isn’t a full ‘write random data to every block in the drive’ erase, but should still be secure enough for most purposes.

Upgrading from m.2 SATA to Crucial NVMe drive on Latitude 7490


Dell Latitude 7490 with existing SATA m.2 SSD. We want to upgrade to larger NVMe drive (Crucial 1Tb).

First tried new drive in Startech NVMe USB enclosure (M2E1BMU31C). Downloaded Crucial cloning software (locked version of Acronis). Problem – not recognised as Crucial drive so Acronis won’t run.

Posts suggest that the new drive should be installed in the laptop first and the system booted via USB. So take current drive out and put it in a SATA USB m.2 enclosure. Attach this to USB-C port and reboot.

This doesn’t work. What does work is attaching it to a USB-A port instead. Then it boots with no intervention.

After that the disk was clones (with no reboot necessary!), the old dive disconnected and the system booted happily from the new drive.

Dell Latitude 7490 freezing when unplugging USB3 WD15 dock

Setup – Dell Latitude 7490 running Ubuntu 18.04 Bionic and Dell WD15 USB-C dock.

Problem – system freezes when dock unplugged.

This problem started after updates. The solution found was to revert to the previous kernel (4.15.0-43-generic) from 4.15.0-44-generic. Did this by setting GRUB to remember the boot setting – change /etc/grub/grub with:


and run


Then hit esc at the loading screen to get to the grub menu.

Opening Dell P2241Hb TFT monitor

Note that you get into this via the front bezel (there’s no handy pry gaps or slots unfortunately). The grey surround and the back are not meant to come apart.

Note that the electronics box is attached to the lcd by a couple of bits of tape only. It’s attached to the back by four screws.

Reset BIOS Admin password on Optiplex 780 SFF

To reset BIOS passwords on Optiplex 780 (small form factor shown here);

  1. Power off system and remove jumper (normally blue) from PSWD1
  2. Boot system – BIOS should alert about password disabled.
  3. Power down and replace jumper
  4. Password should now be cleared – check in BIOS settings.
Dell Optiplex 780 Small Form Factor BIOS password reset jumper.
Dell Optiplex 780 Small Form Factor BIOS password reset jumper.

Seagate DiscWizard insisting on reboots

Sometimes Seagate DiscWizard insists on rebooting, even if you’re cloning between two non-system drives. It is worth checking the state of the target drive. I found that even with no partitions, a target drive with a GPT partition table caused this issue. Solved by firing up diskpart:

list disk
select disk {number}

This wipes the partition table (and consequently the disk appears in the Disk Management console as not initialized). DiscWizard should then clone to it without complaints.

Talysurf in upper JIF lab

The Talysurf software on the laptop in the upper JIF lab sometimes fails to find it’s licence. This is usually because it only checks the license against the first network interface it finds, which is often the WiFi interface (the license is locked to the cabled ethernet interface).

The solution is to disable the wireless interface in the network interfaces window.