Hello,
Please keep the discussion on-list, for the sake of others searching for the same infos.
On Tue, Sep 5, 2017 at 7:43 AM, ingegneriaforense@alice.it ingegneriaforense@alice.it
Plug it in, dump it without mounting any eventual partitions, and you're
done. You can derive from threre for other interfaces like SATA...
Please, about Raspberry, are you sure that plugging a usb drive into it, any partitions will not be mounting ? Maybe you have the Raspberry and you have noticed this behavior ?
I don't own a raspi, just another SBC like it. There is no PC BIOS on it, there is firmware for booting, but (I may be wrong) it is not active after boot.
The automounting of partitions is a property of the operating system, so you should make sure to disable it if you don't want your usb keys to be automounted,
Just search in the docs of your linux distribution of choice for a way to do that, should be fairly straightforward. (subjects to search: automount, udev, systemd, sysv-init, etc...)
I'll check to understand better the raspberry chain: BIOS->PAYLOAD->KERNEL contacting the Raspberry technical support.
I don't think you'll met a lot of ARM SBCs with coreboot, they are mostly using the u-boot bootloader.
But the important thing for you is that the firmware is not used after boot and that the OS don't touch the HW. So, as long as the USB key is only plugged after boot, the firmware won't have the chance to touch it.
After that a simple:
dd if=/dev/sdX of=$HOME/usbkeyimage.raw bs=1M
and you should have a copy of it to search what you're after.
If you're paranoid, make three distinct copies, sha256sum the key, etc...
You should learn how to use those tools.
But beware this is only scratching the surface, if you're after someone who knows his thing, you'll have to eventually go deeper, as some disk firmwares have already been modified to hide some data even from the OS.