GitHub hack reportedly adds Variable Shutter and BIG6 to Sony A7S III

By Tom Whitfield

A GitHub hack has reportedly added Variable Shutter and BIG6 to the Sony A7S III, with the Reddit poster saying one write can make the hidden setup native and permanent in the camera’s Backup memory.

Reddit user CoupleMother1623 posted the technical claim and linked the GitHub project, presenting it as the next step in an ongoing camera-hacking effort. Their explanation begins with access through a concealed path: “The camera exposes a hidden update channel (Jiritsu) over USB even in normal Mass Storage mode.”

The procedure writes files into /tmp/jiritsu/ and places a libJit.so library there for the camera’s updater to load.

The exploit reaches beyond a visible menu item. CoupleMother1623 said the updater calls dlopen on that library, whose _init constructor executes as root inside im.elf, the main application process. They also say the path permits shell commands and small freestanding C++ payloads. No independent reproduction or security review appears in the report.

What does the hack actually change?

The claimed result is native access to the hidden Variable Shutter and BIG6 items, with a settings screen that displays a flicker-frequency value such as 60.0. The report does not define BIG6, explain its shooting behavior, or provide captured-image comparisons showing what either option changes.

• Model-specific visibility records determine which firmware menus appear.
• Per-mode tables use a 20×u16 structure, meaning 20 unsigned 16-bit values per table.
• “Greyed-out” flags and cached copies in .bss also have to be patched in RAM.

The hack patches those controls in RAM, making the entries visible and clickable. That explains the immediate result, but it also defines the limit: the report presents a runtime modification, not a distributed Sony firmware feature.

Takeaway: The menu change may be native in appearance, but the published account still describes an unofficial code-execution path.

Does the change survive a reboot?

Here the source draws a distinction photographers should not blur. The exploit and RAM patches disappear after a reboot, and the procedure does not modify firmware. The camera’s persistent Backup memory can accept a direct write, and those writes reportedly survive reboots.

They say that single write can make the entire Variable Shutter setup fully native and permanent. That is the strongest durability claim in the account, and it remains the poster’s assertion: the report shows no restart-by-restart test or independent check of the saved setting.

That missing validation matters to working photographers. A visible setting is not the same as a stable feature, and the report does not establish whether the saved configuration survives later firmware changes, factory resets or normal menu edits. It also offers no evidence about battery use, recording behavior, RAW output or the effect of the added controls on client images.

For studios, the sensible revenue and workflow conclusion is narrower than “the camera now supports Variable Shutter.” Until another photographer reproduces the full installation and checks frame output, the method cannot safely become a standard camera configuration for paid assignments or a promise to clients.

Takeaway: One persistent write is claimed, but repeatability, image results and update compatibility remain untested.

Can the hack reach other Alpha cameras?

CoupleMother1623 framed wider support as a goal rather than a result: “I am curious to see what’s coming next and if we can expand the hack to work on all current Alpha cameras.” The report identifies only the A7S III as successfully modified, so broader compatibility should not be inferred from the camera-specific menu tables or the A7S III result.

There is also a security limit worth stating plainly. Because the described payload runs as root and can execute shell commands, any installed library should be treated as privileged system code, not as a cosmetic firmware option. The source does not discuss vendor support, warranty consequences or a containment mechanism beyond erasing the runtime work at reboot.

Takeaway: A7S III support is the reported achievement; every other Alpha model remains an unproven target.

The next meaningful milestone is independent A7S III testing that documents exactly what survives a reboot and what the added controls do to captured frames, before photographers build a client workflow around it.