Copyleft

Copyleft is a general method for making a program or other work free and requiring that all modified and extended versions remain free as well. Rather than abandoning copyright, copyleft licenses use it strategically: where proprietary developers use copyright to take away users' freedom, copyleft uses the same legal mechanism to guarantee it. The result is that the code and its freedoms become legally inseparable — anyone may use, study, modify, and redistribute the work, but only on the condition that they pass those same rights along. Freedom, made viral by contract.

Strong vs weak copyleft

Strong copyleft, embodied by the GPL, extends its obligations to any larger work built from the covered code, so the whole derivative must be released under compatible terms. The AGPL closes the network loophole by extending the obligation to software users interact with over a network, even when no binary is ever distributed. Weak copyleft, used by the LGPL and the Mozilla Public License, limits the reciprocal obligation to the original files or library, allowing them to be linked into proprietary applications while still protecting the open component itself. The choice among them is a statement about where the boundary of guaranteed openness should sit: around everything the code touches, or only around the code itself.

Why it suits sovereign hardware

For mining firmware and tooling, copyleft answers a threat this industry knows intimately: the vendor-locked black box. A miner's machine runs someone else's binary, phones home on someone else's schedule, and can be bricked, throttled, or fee-adjusted at a distance. Copyleft prevents the community's answer to that from being quietly re-enclosed — anyone who distributes a modified build must publish the corresponding source, so improvements stay auditable and forkable, and no downstream vendor can take community work proprietary and lock users out of their own hardware again. This is why D-Central releases its open projects, including DCENT_OS, under GPL-3.0: the firmware exists to give operators control of their machines, and copyleft is the legal mechanism that makes that control permanent rather than revocable. It is also an honest acknowledgment of debt — the work stands on decades of GPL-licensed predecessors, from the Linux kernel outward, and passing the same terms forward is how the ratchet keeps turning.

GPLv3 added a clause with particular resonance for mining hardware: its anti-tivoization terms require that when covered software ships in a consumer device, the installation information needed to run modified versions must ship too. Source code you can read but never install on your own machine is freedom in name only — and locked-down bootloaders on mining hardware are exactly the practice the clause exists to answer.

The trade-offs, honestly

Copyleft is not free of cost. Commercial adopters wary of reciprocal obligations sometimes avoid GPL code entirely, which can slow adoption relative to permissive alternatives; license-compatibility questions between copyleft variants create genuine legal homework; and enforcement ultimately depends on copyright holders willing to press the issue. Projects that prioritise maximum uptake — reference libraries, protocol implementations meant to be embedded everywhere — often choose permissive terms deliberately, and reasonably. The question for any project is which failure mode is worse: code that spreads widely but can be closed, or code that spreads more slowly but cannot. For firmware controlling hardware people depend on, we think the answer is clear.

Copyleft is one end of a spectrum; the opposite end is the permissive license, which lets recipients re-license or close derived works freely. Understanding the difference — and what each guarantees the user rather than the developer — is essential before contributing to or forking any open mining project.