Two weekends and $100 of AI subscription gave a 2016-year-old Fujifilm camera 23 new features: FujiMod and this wave of "AI modding camera firmware"

A Notion engineer used AI coding tools to reverse engineer the firmware of the Fujifilm X70, and built a homebrew firmware you can try in the browser and install without flashing. It got 169 stars in 22 days. That's not many, but it's the most complete Fujifilm project in this wave of "AI jailbreaking cameras." Below: how it got started, who else is racing in this wave, and where to start if you want a project that earns stars too.

A comment on Hacker News

In Oct 13 2026, on a Hacker News thread about how Anthropic was redoing version control, longtime user jitl (Jake Teton-Landis, an engineer at Notion) left a comment: over the past two weekends, he had a repo for "modding Fujifilm camera firmware" that grew from nothing to dozens of GB. It had an emulator for the old ARM chips in the X70 (a 2016-year-old camera), a virtual machine running the new X100VI system (2024), a full rewrite of the X70 software stack in C, and a pile of tools that inject code over USB into a camera while it's booting.

The most important line in his comment: "I really didn't want to brick the camera, so I built a deterministic emulator for end-to-end testing. Without AI, I'd have had to write all of it by hand and probably would have just tested directly on the camera. With AI, I got simulated testing, at the cost of burning $100 on the subscription."

Someone asked below: are you going to open source it?

Two days later, on 10-15, the repo justjake/fujimod was created, and the author tagged it ai-slop in the topics.

What it actually is

A homebrew firmware for old Fujifilm cameras that have stopped getting updates, starting with the X70 and bodies with the same generation of processor (EXR Processor II). The official site fujimod.com lists more than 20 new features, many of which photographers have been asking for for years and Fujifilm never delivered:

• "Highlight metering" and "snapshot focus" (one button press jumps focus to a preset distance), both labeled "inspired by the Ricoh GR III";
• 65:24 and 17:6 style wide aspect ratios, with desqueezing for anamorphic lenses;
• F-Log video, HDMI output, and finer JPEG compression;
• Custom film simulations, saving recipes as files, and pinning them to C1–C7;
• Automatic date-based folders, and rebinding the dials and aperture ring to other functions.

What's open source on GitHub is the periphery: a Rust USB protocol library, the emulator, and the web-based USB tool. The firmware patches themselves are not open source.

What really sets it apart from others is three design choices that reduce fear:

1. Try it in the browser first. The site runs a simulated camera where you can click through the original firmware and the modded version, so you don't risk a real camera. FujiRumors, when promoting it, specifically wrote "you can see these features right on the website without installing anything on your camera."
2. Dual-boot from an SD card. No flashing. Pull the card and you're back on stock firmware. The first line of the repo description is in all caps: "Do not flash custom firmware into your camera before dual-boot is working."
3. You upload the official firmware yourself, and patching happens locally in the browser. The site doesn't distribute modified firmware, which sidesteps copyright trouble.

There's also a small feature for testers: holding the left Fn button together with DISP/BACK on the camera saves a diagnostic report to the card and shows a QR code on screen. Connect over USB to the site and you can file a bug.

Why this month

In one sentence: AI coding tools suddenly lowered the barrier to firmware reverse engineering, and owners of old Fujifilm cameras had been holding in a lot of demand.

On the demand side: small cameras like the X70 and X100 have had their used prices driven up by the retro-digital look on TikTok (PetaPixel reported in 2022 that used X100 prices had risen to about $1,000, and on eBay an X70 now goes for over $800), yet Fujifilm stopped updating their firmware long ago. Owners holding an expensive, beloved camera that the manufacturer no longer supports have strong feelings.

On the supply side: in the same month, Sony, Nikon, Ricoh, Hasselblad, and Olympus all had batches of repos for "AI helps me reverse engineer firmware." This wasn't one person's coincidence. It was a platform event.

Where the stars came from

Daily stars (GitHub, from 10-26):

A few things worth noting:

Ask for the wishlist first, then ship. In October, the author posted "I'm building custom firmware, what's on your wishlist?" on r/fujifilm. When 0.0.1 came out, the feature page on the official site listed "Surface View", "F-Log", "dial unlock" and "folders by date", each credited "THANKS: suggested by u/someone" and linked back to that comment. Anyone who suggested a feature and saw their name on it is likely to share it.

The stars came from photography circles, not developer circles. The author didn't post a Show HN and didn't hit the HN front page. On X, almost nobody mentioned fujimod in nearly 30 days, apart from FujiRumors' own post. The traffic came from photography media and photography YouTube creators.

Beyond stars, people are actually building. In 22 days there were about 1,682 commits from 14 contributors. Recent issues and PRs are mostly owners of the X-T2, X-T5, X-T30, X100VI, and X-Pro2 adapting the project to their own bodies (GitHub, 11-06). 23 forks, over a tenth of the stars, which is high for a firmware project.

Who it's competing with

FujiMod gained +111 in the last 7 days, about the same as the Sony and Nikon projects (+136 and +134). It doesn't have the most stars, but most others stop at "research notes" or "patch scripts." FujiMod is the one that turned into something a hobbyist who can't code dares to try.

Where it falls short

• The range of bodies is narrow. Only the X70 generation really works. The X100V/VI and X-T series, which have the most owners, are still being ported one body at a time by the community.
• The core isn't open source. The firmware patches aren't public. What the community can contribute is adaptation and testing, not changing features.
• Other brands don't have a "productized" version. The Sony, Nikon, and Ricoh repos have more stars, but none of them has the full set of browser simulation, dual-boot, and local patching.
• Legal risk hangs over it. Whether Fujifilm will send a legal letter is unknown. My guess: the more famous it gets, the bigger the risk.

If it were you

Verdict: B. Worth trying. FujiMod makes the case clearly: an emotionally invested group of owners of an old device, plus "AI makes reverse engineering cheap," plus the safety of "try it in the browser first, no flashing," means photo media and creators will actively promote it. But the barrier is high: you need real reverse engineering skill, you need the camera in hand, and you have to accept the risk of bricking and legal trouble. The star ceiling isn't high either; the biggest in this wave has only 1,118. And this month dozens of repos have already crowded in, so the window is closing.

Who it suits: people who know embedded systems or reverse engineering, who happen to own a device the manufacturer has stopped supporting but that still has devoted fans (a certain generation of Sony black cards, the Ricoh GR II, older Olympus bodies, older DJI action cams), and who are willing to spend a few weeks making it something an ordinary person dares to install.

Who it doesn't suit: people without the hardware who only want to publish a research-notes repo (dozens of those already exist this month), and people who care about legal risk or don't want to maintain a community of owners.

How to do it. Three options, ranked by how worth it they are:

1. Do a "productized" version for another brand. Pick a camera that has stopped updates, has high used prices, and has passionate owners, and copy FujiMod's playbook in full: browser emulator, SD card dual-boot, local patching of user-supplied official firmware, and a feature catalog with screenshots. The Sony and Ricoh projects have more stars but are still at the research level, so that position is open.
2. Build the shared base for this wave. Many repos keep rebuilding the same emulator, USB protocol, and patching framework. A cross-brand "camera firmware emulator / patch toolchain" would let latecomers skip starting from zero, and the stars would come from fellow developers, not from one model's owners.
3. Add bodies to FujiMod. Owners of the X100V/VI and X-T series are the largest groups. Adapting for them via PRs is the lowest-risk way to build reputation and a track record, though the stars go to someone else's repo.

How to get users: follow FujiMod's order. First, go to that camera's subreddit or Facebook groups to collect wishlists, and put the suggesters' names on the feature page at release. Then email brand-focused media like FujiRumors (SonyAlphaRumors, and enthusiast sites for Ricoh), with a link to a demo you can play in the browser. Finally, photography YouTubers, who are currently making "AI jailbreaking cameras" content and need fresh material. Don't count on X or HN, since they barely contributed this time.

When to act: the sooner the better, ideally before the end of 2026. The wave only started in October, and photography creators are still posting "AI jailbreaks camera" videos. In two or three months the media will be tired of this angle.

Signs you've misread it: ① Fujifilm or Sony sends legal letters against projects like this, or the repos get taken down, meaning this path is closed; ② by mid-November, FujiMod and the Sony and Nikon repos are adding single-digit stars a day, meaning the wave has passed; ③ conversely, if a brand ships a version with the same "try in browser, dual boot" approach that hits 1,000 stars within a month, the ceiling is higher than estimated here, and you need to move faster.

Data and sources

GitHub: justjake/fujimod repo page, daily stars and forks (10-26 to 11-06), issues and contributors; star counts for similar repos (11-06). Hacker News: comments by jitl 10-13 and 10-27. Reddit: two posts in r/fujifilm (upvotes and comment counts not retrieved). Website: feature page at fujimod.com and the 0.0.1 release notes. Media: FujiRumors 10-16 and 10-31, Digital Camera World 10-21, barbano.com 11-02, PetaPixel 2022 and its 100 coverage of X-series used prices. YouTube: Breno Loves Cameras 10-29 and FUTC 11-01 video view counts (11-06). Whether Breno's video directly demonstrates FujiMod is unverified. Where text says "inference" or "unverified", that is the status.