Raspberry Pi RAM Restrictions No Huge Deal, Frankly

Hacking on Raspberry Pi board internals is certainly one of my favorite matters. I do know a bunch of obscure issues about these cute little boards. Three years in the past, I lined a Raspberry Pi 4 RAM upgrade story. Getting a BGA RAM chip and swapping it in appeared like a no brainer to me – other than all of the quite a few unsure components about it, you recognize. It was a pleasure to see hackers pull it off, and for it to perform in addition to it did!

Things modified. You can’t actually get RAM chips anymore. You can also’t get RAM sticks. You can’t get even SSDs with RAM chips on them. Even getting Raspberry Pi boards could be laborious until you recognize the place to look. This is the place a recent three-minute video by [Jeff Geerling] finds us.

Turns out, Raspberry Pi Foundation pushed binary-blob bootloader adjustments that restrict your capability to improve RAM. I’ve identified about it since final 12 months by means of the grapevine, and someway, as I examine it, this didn’t trouble me in any respect. Not sufficient to write down a Hackaday article about it, even, a lot much less discuss it extra broadly. Why didn’t it trouble me? Today, I sat down and contemplated this for a bit.

Here’s my conclusion: I don’t assume it’s a giant deal in any respect, even when evidently many individuals would disagree. Come in, as you might be, and I hope you discover my ideas on the scenario entertaining.

How It’s Made

First, some floor info. This change restricts upgrading the RAM chip in your Pi 4 and Pi 5, in addition to Compute Modules. By the appears of it, it doesn’t prohibit changing the RAM chip with a chip of the same measurement, quote, “locking units to their unique RAM measurement”. As such, this doesn’t forestall restore of your Raspberry Pi board, however does considerably restrict your restore half alternative, at most.

This restriction is definitely bypassable. The bootloader is saved within the SPI flash chip, which could be reflashed utilizing the built-in masks ROM over USB and rpiboot, and you aren’t prevented from flashing older variations of the bootloader, to this point. This means even when you manually swap the RAM chip, all it’s essential do is to additionally downgrade the bootloader to the final identified good launch — 2024-09-10 — after which your Pi board or Compute Module will perform with upgraded RAM. If you could have the talents to improve your RAM, you most definitely have the talents to downgrade the Raspberry Pi bootloader.

For most common use, having a two-year outdated bootloader model gained’t actually matter. There have been about 15 releases for the reason that 2024-09-10 one, so I went and skim by means of the patchnotes. Checking shortly, the essential options like NVMe boot have been obtainable for a good bit earlier than this launch, possibly you’ll miss out on just a few high quality of life fixes or extra obscure {hardware} configuration issues, however that’s it. Hopefully I’m not lacking one thing, please level it out if I’m. You know what is a matter, by the way in which? The patch notes for the 2024-09-23 release don’t point out the RAM measurement test addition in any respect, possibly they need to repair that.

What’s humorous is, I’m checking experiences and evidently the board will boot and function well with newer bootloaders (mostly 2025 versions), and in different circumstances (principally however not always 2026 bootloader versions) it will outright refuse to boot with a 8 or 9 flash failure code. I haven’t in contrast particulars on what precisely is likely to be inflicting this but, however it is likely to be that you just don’t even must downgrade bootloader all that badly – although I’d positively begin with the oldest known-good launch.

How It Happened

This is the primary motive I can’t carry myself to care. If you may improve your RAM, you may downgrade the bootloader. However, right here’s the purpose of rivalry – did this variation really want to occur?

For the reference, this bootloader change occurred virtually precisely two years in the past, sooner or later between September 10 and September 23, 2024. This was precisely a 12 months and a half after we lined the primary Raspberry Pi RAM improve. What modified?

The Raspberry Pi Foundation (RPF) justifies this as follows: they noticed third-party resellers sourcing low-RAM Compute Modules, upgrading them with RAM from unknown supply and unknown stability. My remark is that they’d even be reselling the modules at a markup for purely business achieve, whereas undercutting RPF who would in any other case direct that cash into RnD, one thing I a lot get pleasure from to see them do. This creates perverse incentives and danger for individuals shopping for Raspberry Pi boards on-line, and RPF determined to restrict this primarily for his or her customers’ profit, plus, when you ask me, a few of theirs.

Is this justification true? I can’t know, however I went to test for indicators of this occurring, and the non-consensual RAM switcheroos appears to be occurring everywhere! The associated GitHub points have a good few pingbacks, and exploring them makes the issue look grim to me.

Off the cuff, I spent 15-20 minutes checking, and I can simply discover fifteen completely different individuals on GitHub alone complaining about this failure. [(1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) (14) (15)] As far as failure modes in common {hardware} go, it is a surprisingly giant quantity that means not less than lots of of hackers and hobbyists affected, if no more. None of them seem to have carried out the improve themselves, sizzling air and flux manner, the Hackaday manner – all of them seemingly merely purchased a “8 GB” model from both Aliexpress or Amazon. In not less than one case, the seller immediately lied to the buyer in regards to the challenge and did under no circumstances admit that an improve happened, regardless that it clearly did.

How It Makes Sense

This appears to map precisely to what RPF says occurred. I can very a lot see why they’d be nervous. For occasion – on the time they made this variation, if my reminiscence isn’t failing me, CM5 or CM4 2 GB boards went for $30-$40, 8 GB boards went for $100ish, and 4 GB boards have been someplace inbetween. As far because the intersection of hacker devices and industrial-lite {hardware} goes, that worth is greater than honest.

At this level, we’re not speaking about individuals upgrading RAM on their boards for enjoyable, and bear in mind, you may nonetheless do all of that. Instead, that’s a good bit of margin for somebody to seize for 20 minutes of sizzling air work, somebody who hasn’t accomplished any of the RnD that RPF has put in. I personally a lot somewhat would see that margin go to RPF, and I’d wish to have them take care of not one of the headache, too.

Creating incentives for this type of switcheroo trade, unimpeded, appears deeply corrosive to me. For one, there’s zero repercussions for somebody equipping these boards with substandard and harvested chips. RPF, as any skilled {hardware} firm, would learn about sourcing harvested or in any other case shady-origin RAM and different chips. A 3rd occasion on Amazon/Aliexpress passing on these chips undisclosed to unqualified finish customers, now that goes far past the same old harvested chip horror tales. It turns right into a sport of “will/gained’t the consumer discover the weirdness and ask the vendor for a refund on time”, and at $100-$200, along with the ship-item-back requirement these costs carry, the reply will typically be “no”. Now, the customer finds out in regards to the tampering virtually instantly, since Raspberry Pi boards auto-update the firmware.

If you don’t agree that this alone is corrosive – discover how this type of “upgraded” board clearly requires sellers to misrepresent what they’re promoting? You’re not going to seek out about this “improve” within the itemizing, there gained’t be a “8GB reworked” label, clearly that may require decreasing the value and/or slicing into the margins. Just like there’s no incentive for utilizing a contemporary RAM chip as an alternative of a harvested one, there’s additionally zero incentive to be open in regards to the mod. That’s no solution to promote a pen, a lot much less a full laptop.

How RPF Does Things

Here’s essentially the most complicated half to me. I’m seeing [Jeff] and others say that that is out of character for RPF to do. This doesn’t appear true to me, in any respect? I don’t recall a time when Raspberry Pi has put effort into giving customers freedom to hack on the board itself as quickly as any type of authorized or competitors challenge arose.

Raspberry Pi places cryptographic EEPROMs on Pi Camera boards, v2 and past, to thwart clone cameras that grew to become so prolific and low-cost with v1, I personal not less than 5 of these clones in several form-factors. I don’t prefer it, however not less than the authenticity checks are disabled for Compute Module variations, so far as I bear in mind. They nonetheless don’t promote the MLX7704 PMIC that immediately dies when you by chance short-circuit GPIO header 5 V to three.3 V, two male pins which can be proper on the facet of the board and exceptionally simple to short-circuit from three sides concurrently.

Raspberry Pi solely ever publishes “lowered” schematics, ever since 2013, and so they haven’t even launched these for Pi 5. Neither have they printed Pi 4 USB-C issue repair schematics despite having promised to do so. Half of the chips on a contemporary Raspberry Pi board are single-source and board-specific, the aforementioned PMIC being a enjoyable instance. Raspberry Pi boards ship closed-source software program, from the bootloader to the GPU code whipping the CPU, to all of the onboard wi-fi chips they’ve used to this point, and this brings actual points you’ll encounter as you push the boundaries. The JTAG port has at all times been locked down, and even the bootloader is cryptographically signed – no patching out the RAM test code, sorry to spoil it.

I’m removed from accomplished itemizing methods by which Raspberry Pi prevents or works in opposition to low-level board tinkering, there’s not less than 5 extra issues I might listing from reminiscence if I have been bothered to test them totally sufficient proper now. Point is, if anybody got here to Raspberry Pi for the low-level hackability of the {hardware}, there was by no means a scarcity of causes to look elsewhere. That was by no means the upside.

I don’t assume low-level board hackery is what individuals genuinely anticipate from Raspberry Pi in any respect, even when they could say that they do – as a result of it was by no means actually there. You can’t genuinely anticipate one thing that was barely ever current. In distinction, there’s loads of competitors that publishes full board schematics, typically even gerbers, makes use of as a lot open code as potential, doesn’t signal bootloaders, and so forth. Raspberry Pi isn’t open or hackable {hardware} by these metrics, and it by no means was. It’s not hackable {hardware} anyplace as a lot because it’s {hardware} made for hackers to make use of, and there’s clearly a giant distinction.

How Did We Get Here?

In observe, individuals clearly come to Raspberry Pi due to their group within the thousands and thousands, meticulously explored and documented {hardware}, unmatched availability of boards and software program alike, having options for nigh each little niggle and nitpick, RPF’s capability to experiment and launch new cool {hardware} 12 months after 12 months, and even new requirements they create alongside the way in which. Most of low-level issues get papered over by means of sheer scale – say, final 12 months [Jonathan Clark] reverse-engineered the Raspberry Pi Zero 2 W, after which [TubeTime] reverse-engineered the Compute Module 5, how cool is that?

I might agree with [Jeff Geerling] that it might as an alternative profit from a “guarantee bit” sort of mechanism, however actually, the bootloader downgrade isn’t that onerous of a penalty, and “board autoupdates firmware, fails on subsequent boot” is a a lot stronger indicator that it’s best to go get a refund at haste. A refund can be manner simpler to get when you say “hey, the board stopped working instantly”, and who is aware of, possibly you’ll get a refund and get to maintain the board so as to downgrade its firmware and nonetheless use it! Win-win, vendor loses out on promoting you a shady board, and also you get a shady board which may simply work, without spending a dime. Chances are, we wouldn’t even be speaking in regards to the RAM swap restrictions if it weren’t for the RAM scarcity, and that isn’t RPF’s fault in any respect in anyway.

My recommendation: don’t lament Raspberry Pi RAM upgrades, particularly given they’re solely barely more durable to carry out now. Very few hackers ever carried out them, the primary viewers for them turned out to be dodgy {hardware} resellers on-line, and usually, restore doesn’t appear to be impeded in any respect, both.

Think of the customers that may not be fooled by a shady vendor on Amazon, particularly now that the perverse incentives for board mods and reusing harvested RAM chips are at their highest. RAM shortages may make any RAM subject damage deeper than normal, which to me is the most certainly motive we’re discussing this in 2026 as an alternative of 2025, however this variation is much extra possible to assist a hacker in observe, than it’s to harm.