Battery Repair By Reverse Engineering

August 26, 2025 by Tyler August 28 Comments

Ryobi is not exactly the Cadillac of cordless tools, but one still has certain expectations when buying a product. For most of us “don’t randomly stop working” is on the list. Ryobi 18-volt battery packs don’t always meet that expectation, but fortunately for the rest of us [Badar Jahangir Kayani] took matters into his own hands and reverse-engineered the pack to find all the common faults– and how to fix them.

[Badar]’s work was specifically on the Ryobi PBP005 18-volt battery packs. He’s reproduced the schematic for them and given a fairly comprehensive troubleshooting guide on his blog. The most common issue (65%) with the large number of batteries he tested had nothing to do with the cells or the circuit, but was the result of some sort of firmware lock.

It isn’t totally clear what caused the firmware to lock the batteries in these cases. We agree with [Badar] that it is probably some kind of glitch in a safety routine. Regardless, if you have one of these batteries that won’t charge and exhibits the characteristic flash pattern (flashing once, then again four times when pushing the battery test button), [Badar] has the fix for you. He actually has the written up the fix for a few flash patterns, but the firmware lockout is the one that needed the most work.

[Badar] took the time to find the J-tag pins hidden on the board, and flash the firmware from the NXP micro-controller that runs the show. Having done that, some snooping and comparison between bricked and working batteries found a single byte difference at a specific hex address. Writing the byte to zero, and refreshing the firmware results in batteries as good as new. At least as good as they were before the firmware lock-down kicked in, anyway.

He also discusses how to deal with unbalanced packs, dead diodes, and more. Thanks to the magic of buying a lot of dead packs on e-Bay, [Badar] was able to tally up the various failure modes; the firmware lockout discussed above was by far the majority of them, at 65%. [Badar]’s work is both comprehensive and impressive, and his blog is worth checking out even if you don’t use the green brand’s batteries. We’ve also embedded his video below if you’d rather watch than read and/or want to help out [Badar] get pennies from YouTube monetization. We really do have to give kudos for providing such a good write up along with the video.

This isn’t the first attempt we’ve seen at tearing into Ryobi batteries. When they’re working, the cheap packs are an excellent source of power for everything from CPap machines to electric bicycles.

Thanks to [Badar] for the tip.

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How Intel’s 386 Protects Itself From ESD, Latch-up And Metastability

August 21, 2025 by Maya Posch 11 Comments

To connect the miniature world of integrated circuits like a CPU with the outside world, a number of physical connections have to be made. Although this may seem straightforward, these I/O pads form a major risk to the chip’s functioning and integrity, in the form of electrostatic discharge (ESD), a type of short-circuit called a latch-up and metastability through factors like noise. Shielding the delicate ASIC from the cruel outside world is the task of the I/O circuitry, with [Ken Shirriff] recently taking an in-depth look at this circuity in Intel’s 386 CPU.

The 386 die, zooming in on some of the bond pad circuits. (Credit: Ken Shirriff)

The 386 has a total of 141 of these I/O pads, each connected to a pin on the packaging with a delicate golden bond wire. ESD is on the top of the list of potential risks, as a surge of high voltage can literally blow a hole in the circuitry. The protective circuit for this can be seen in the above die shot, with its clamping diodes, current-limiting resistor and a third diode.

Latch-up is the second major issue, caused by the inadvertent creation of parasitic structures underneath the P- and NMOS transistors. These parasitic transistors are normally inactive, but if activated they can cause latch-up which best case causes a momentary failure, but worst case melts a part of the chip due to high currents.

To prevent I/O pads from triggering latch-up, the 386 implements ‘guard rings’ that should block unwanted current flow. Finally there is metastability, which as the name suggests isn’t necessarily harmful, but can seriously mess with the operation of the chip which expects clean binary signals. On the 386 two flip-flops per I/O pad are used to mostly resolve this.

Although the 386’s 1985-era circuitry was very chonky by today’s standards, it was still no match for these external influences, making it clear just how important these protective measures are for today’s ASICs with much smaller feature sizes.

It’s A Pi, But It’s Not Quite A Raspberry Pi

August 17, 2025 by Jenny List 17 Comments

When is a Raspberry Pi not a Raspberry Pi? Perhaps when it’s a Pi Pico-shaped board with an RP3A0 SoC from a Raspberry Pi Zero 2, made by [jonny12375].

Back in the early days of the Raspberry Pi, there was a offering from the Korean manufacturer Odroid, which wasn’t merely a similar machine with a different SoC, but a full clone in a smaller form factor featuring the same BCM2385 chip as the original. It was electrically and software-wise identically to the real thing, which we suspect didn’t go down very well with the Pi folks in Cambridge. The supply of Broadcom chips dried up, and ever since then the only way to get a real Pi has been from the official source. That’s not quite the end of the unofficial Pi story though, because a few hardy experimenters have made Pi clones like this one using chips desoldered from the real thing.

It’s the fruit of a reverse-engineering project to find the chip’s pinout, and it’s a proof of concept board rather than the intended final target of the work. The process involved painstakingly sanding down each layer of a Zero 2 board to reveal the traces and vias. The current board has a few quirks but it boots, making this an impressive piece of work on all counts. We’re looking forward to seeing whatever the final project will be.

If you’re hungry for more Pi-derived goodness, we’ve also seen one using the part form a Pi 3.

Reverse Engineering A ‘Tony’ 6502-based Mini Arcade Machine

July 21, 2025 by Maya Posch 15 Comments

The mainboard of the mini arcade unit with its blob chip and EEPROM. (Credit: Poking Technology, YouTube)

For some reason, people are really into tiny arcade machines that basically require you to ruin your hands and eyes in order to play on them. That said, unlike the fifty gazillion ‘retro consoles’ that you can buy everywhere, the particular mini arcade machine that [David Given] of [Poking Technology] obtained from AliExpress for a teardown and ROM dump seems to have custom games rather than the typical gaggle of NES games and fifty ROM hack variations of each.

After a bit of gameplay to demonstrate the various games on the very tiny machine with tiny controls and a tiny 1.8″, 160×128 ST7735 LC display, the device was disassembled. Inside is a fairly decent speaker, the IO board for the controls, and the mainboard with an epoxy blob-covered chip and the SPI EEPROM containing the software. Dumping this XOR ‘encrypted’ ROM was straightforward, revealing it to be a 4 MB, W23X32-compatible EEPROM.

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Video Game Preservation Through Decompilation

June 23, 2025 by Tom Nardi 18 Comments

Unlike computer games, which smoothly and continuously evolved along with the hardware that powered them, console games have up until very recently been constrained by a generational style of development. Sure there were games that appeared on multiple platforms, and eventually newer consoles would feature backwards compatibility that allowed them to play select titles from previous generations of hardware. But in many cases, some of the best games ever made were stuck on the console they were designed for.

Now, for those following along as this happened, it wasn’t such a big deal. For gamers, it was simply a given that their favorite games from the Super Nintendo Entertainment System (SNES) wouldn’t play on the Nintendo 64, any more than their Genesis games could run on their Sony PlayStation. As such, it wasn’t uncommon to see several game consoles clustered under the family TV. If you wanted to go back and play those older titles, all you had to do was switch video inputs.

But gaming, and indeed the entertainment world in general, has changed vastly over the last couple of decades. Telling somebody today that the only way they can experience The Legend of Zelda: A Link to the Past is by dragging out some yellowed thirty-odd year old console from the attic is like telling them the only way they can see a movie is by going to the theater.

These days, the expectation is that entertainment comes to you, not the other way around — and it’s an assumption that’s unlikely to change as technology marches on. Just like our TV shows and movies now appear on whatever device is convenient to us at the time, modern gamers don’t want to be limited to their consoles, they also want to play games on their phones and VR headsets.

But that leaves us with a bit of a problem. There are some games which are too significant, either technically or culturally, to just leave in the digital dust. Like any other form of art, there are pieces that deserve to be preserved for future generations to see and experience.

For the select few games that are deemed worth the effort, decompilation promises to offer a sort of digital immortality. As several recent projects have shown, breaking a game down to its original source code can allow it to adapt to new systems and technologies for as long as the community wishes to keep them updated.

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Hackaday Links: June 22, 2025

June 22, 2025 by Dan Maloney 16 Comments

Hold onto your hats, everyone — there’s stunning news afoot. It’s hard to believe, but it looks like over-reliance on chatbots to do your homework can turn your brain into pudding. At least that seems to be the conclusion of a preprint paper out of the MIT Media Lab, which looked at 54 adults between the ages of 18 and 39, who were tasked with writing a series of essays. They divided participants into three groups — one that used ChatGPT to help write the essays, one that was limited to using only Google search, and one that had to do everything the old-fashioned way. They recorded the brain activity of writers using EEG, in order to get an idea of brain engagement with the task. The brain-only group had the greatest engagement, which stayed consistently high throughout the series, while the ChatGPT group had the least. More alarmingly, the engagement for the chatbot group went down even further with each essay written. The ChatGPT group produced essays that were very similar between writers and were judged “soulless” by two English teachers. Go figure.

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Flopped Humane “AI Pin” Gets An Experimental SDK

June 19, 2025 by Donald Papp 11 Comments

The Humane AI Pin was ambitious, expensive, and failed to captivate people between its launch and shutdown shortly after. While the units do contain some interesting elements like the embedded projector, it’s all locked down tight, and the cloud services that tie it all together no longer exist. The devices technically still work, they just can’t do much of anything.

The Humane AI Pin had some bold ideas, like an embedded projector. (Image credit: Humane)

Since then, developers like [Adam Gastineau] have been hard at work turning the device into an experimental development platform: PenumbraOS, which provides a means to allow “untrusted” applications to perform privileged operations.

As announced earlier this month on social media, the experimental SDK lets developers treat the pin as a mostly normal Android device, with the addition of a modular, user-facing assistant app called MABL. [Adam] stresses that this is all highly experimental and has a way to go before it is useful in a user-facing sort of way, but there is absolutely a workable architecture.

When the Humane AI Pin launched, it aimed to compete with smartphones but failed to impress much of anyone. As a result, things folded in record time. Humane’s founders took jobs at HP and buyers were left with expensive paperweights due to the highly restrictive design.

Thankfully, a load of reverse engineering has laid the path to getting some new life out of these ambitious devices. The project could sure use help from anyone willing to pitch in, so if that’s up your alley be sure to join the project; you’ll be in good company.