I've got two scenarios in mind:

  1. I'm writing some software for a RaspberryPi (in my case, it's a Pi4) and I want to test that software on a "box fresh" Pi.
  2. I want to give my RaspberryPi away to a stranger.

Let's say that I reformat or replace the Pi's SD card before doing either of the above.

With respect to scenario (1): will my Pi now be indistiguishable from a brand new one of the same model?

With respect to scenario (2): supposing that, for the sake of argument, the stranger in question had bad intentions, would he be able to access any data that I might have generated on my old Pi?

  • There's no user generated data stored anywhere on your RPi. There's nothing you need to do before giving it away to a stranger.
    – Dougie
    Apr 24, 2020 at 14:05

1 Answer 1


There is a small, 512KB, EEPROM section in the Pi processor itself that is used for the bootloader. Here is a description:

Pi4 Boot PROM

Normally this is not changed by Raspbian but it is possible to modify it.

So the bottom line is that YES, it's possible that you might write something into an unused portion of the on-board EEPROM that would persist in spite of an SD card swap but NO, under normal use, nothing is changed that could be detected.

  • There's no supported interface to write anything other than the bootcode to that EEPROM.
    – Dougie
    Apr 24, 2020 at 14:02
  • 1
    That doesn't mean it can't be done. It just means you have to do it the old fashioned way. There is code, open source code, to flash a new boot loader. I suspect it is possible to hack that and use it to write new data into it.
    – jwh20
    Apr 24, 2020 at 14:50

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