Hello,
What would be a good practice when buying a second hand laptop?
Should the TPM, the BIOS or the OS be cleaned? Is there a way to make a “factory reset”?
edit: i had to dig more, I just found this topic.
Yes.
TPM - yes, reset to factory default (if there is a TPM)
BIOS - that would be keen but, yes, you should reflash it
OS - that goes without saying always for all laptops ever - you should reinstall the operating system i.e. wipe entire disk and install from scratch
The yes answer was pretty expected. 
I pushed esc at boot for the SeaBIOS menu, then t for TPM configuration.
The current state of the TPM is:
Enabled and active
Ownership has not been taken
A user can take ownership of the TPM
Available options are:
d. Disable the TPM
v. Deactivate the TPM
p. Prevent installation of an owner
I’m afraid to go further without documentation. All I could find is “What is TPM and do I need it?” but that doesn’t answers the question (despite the title) and doesn’t help for configuration.
Yes, that’s the hard part.
If I had a Librem Key, I had to choose PureBoot.
As I don’t, I must flash Coreboot. But Coreboot is an initializer which requires a payload, like SeaBIOS, Tianocore, GRUB2, Linux or Heads.
- Going for Heads is like reinventing what Purism does very well but with my own key instead of the Librem one. Does Purism Pureboot support SoloKeys or Signet keys?
- Going for Linux might make very fast boot at the price of flexibility.
- Going for GRUB2 might help a multiboot but is it required at the BIOS level? May I setup a dualboot for Linux and BSD by another way?
- Going for Tianocore brings an UEFI implementation but is it useful if I can immediately load GRUB?
- Going for SeaBIOS seems the best option as it’s fast, still flexible and is the option used by Purism.
Maybe am I trying to slice an hair in 4? Especially since I need to find all the required firmwares, etc. from scratch. Fortunately Purism’s Coreboot is available ready for use.
Pure OS download and instructions are here: https://pureos.net/download/ and https://tracker.pureos.net/w/installation_guide/.
I also opened the case to check for an “additional” hardware (and above all because I’m curious). This brought me a new question: the HDD seems requiring a caddie or some kind of holder with 2 screw holes close to the SD/MMC port. Where is it possible to find one?
edit: typos
Yes. That’s the safe, supported option. That’s what you will get, I believe, if you use the Purism-provided shell script to do the flashing and you don’t choose PureBoot.
Where did you get this second-hand laptop? From Purism or private sale?
Private. ebay.
I can’t specifically answer your question about the HDD but you should mention what model (13 or 15) and version you have; and it may help to mention what kind of disk is currently in there (if any).
You could always post a photo of what you are looking at.
Many people these days are going NVMe (in new computers anyway) and an NVMe drive will typically require a single screw.
It’s a Librem 15 v4. The system is on an NVMe. Aside of it is a SATA connector and some empty space obviously for an HDD.
