The Least Annoying of All Evils

If you missed the hubbub this week, it was discovered that the Raspberry Pi Foundation added code in the firmware that locks the boot process up if non-original RAM chips are detected onboard. Hot-rodding your Pi is a time-honored tradition in these parts. We do wonder just how many folks are taking the risk of hot-airing the memory off the board, versus paying the extra cash to get one with more RAM. But according to Raspberry Pi, enough boards are showing up that have the RAM surreptitiously replaced, and often defective, that they took the step to lock the machine down.

Should users be alerted to potentially unscrupulous behavior by the companies selling them single-board computers? I think we’d all say “sure”. But should that entirely brick the device? And prevent people from upgrading their own? The hacker in me says “no”. Is there any way to reconcile these two? Our own [Arya Voronova] suggests that it’s no big deal to flash an older version of the initial firmware, and we concur, although it does leave behind all the improvements since 2023, and it will only get less fresh as time goes by.

How to announce that the board has non-factory memory without breaking it? [Jeff Geerling] suggested a non-matching-memory bit that users could check, but then they could also neglect to check. My cellphone has a screen that appears every bootup, and requires me to press the power button to continue, because I rooted the phone and installed an open-source OS. It’s a hassle for sure, but it’s a lot better than bricking the phone or disallowing user firmware entirely.

Doing the same thing for the Raspberry Pi isn’t as easy. You never know what, if any, peripherals are connected, so you can’t guarantee that there’s a screen to alert you or even necessarily a keyboard on which you could acknowledge. We’re reminded of a similar situation with FTDI usb/serial converter chips ages ago. Their driver software simply refused to work with counterfeit versions of their chips. Hackers were up in arms, largely because we couldn’t know if the parts were genuine at purchase time, and the counterfeits were widely distributed even by reliable resellers.

So what about it? Can you think up a tamper-evident signal that could run on boot on a Raspberry Pi, maybe a headless system installed in some difficult-to-reach place? Maybe ideally the equivalent of the cell phone’s scare message? It would have to be hard to overlook, but keep the machine running, notifying the user that things aren’t kosher, but not preventing them from getting to work. Sounds like a tall order to us.