elseif/MikroTikPatch: patching RouterOS and generating licenses in Python

What MikroTikPatch is for

RouterOS is commercial software, and its licence is tied to the hardware or to the CHR instance it runs on. MikroTikPatch targets people who want a RouterOS instance for testing, without buying a licence for every rebuild. The README states the scope directly: the project and its tools are for testing purposes only, and production environments should use the officially licensed version. That sentence is the whole positioning, and it rules out the use case most people arrive with.

The repository covers two architectures. x86 and arm64 are handled by this project, with the homepage at mikrotik.ltd and a demo at demo.mikrotik.ltd. The other list, arm, mipsbe, mmips, ppc, smips and x86, points at routeros.ltd and requires sponsorship, with online direct licensing for CHR on x86 and arm64. So the free path and the paid path are split by architecture, not by feature. If you are on a hAP, a CRS switch or anything else running mipsbe or arm, this repository is not the one you want.

The practical audience is a network engineer or a developer who needs a RouterOS instance to test a configuration, a script or an integration, and who is willing to treat that instance as disposable. The licence bot at t.me/ROS_Keygen_Bot and the option.npk package are the two delivery channels for the licence side, and the Docker image is the fastest way to get an instance without touching hardware.

How the patch and licence mechanism fits together

The repository layout tells you most of the architecture. There is keygen/, npk.py, npkextract/, patch.py, sha256.py, mikro.py, busybox/ and toyecc/, plus chr.sh and setup-routeros.sh at the top level. That is a pipeline: an .npk package is extracted, its contents are modified, hashes are recomputed with sha256.py, and the result is repacked. The patch.py entry point is what applies the modification, and keygen/ is what produces the licence material.

The public key side is the part the repository name points at. RouterOS verifies package signatures against a key it trusts, so a modified package only installs if the signature chain is consistent with what the router expects. MikroTikPatch ships a replacement public key and generates licences that match it. The README does not document the exact key format or where in the image it is substituted, so treat that as something to read from the source if you need to understand it.

On the router side, the licence is granted by installing option.npk. The README says installing that package automatically grants the highest-level licence. That is the entire documented interface: no serial, no activation server, no per-device step. Everything else in the feature guide, container mode, shell access, the CHR to x86 switch, depends on option.npk being present first.

Installing it and a first real use

The fastest path is the Docker image, which the README gives as a single command. It runs a CHR instance with the privileges the kernel needs for the network stack.

docker run -d --privileged --name chr ghcr.io/elseif/chr:latest

After that container starts, you have a RouterOS CHR instance. The README does not list a port mapping or a default credential for this image, so check the container logs before you assume how to reach it.

If you are working from a release instead, the releases are named after the RouterOS version they target, for example 7.25beta5, 7.25beta5-arm64 and 6.49.22. Match the release to your architecture before you download anything.

Once option.npk is installed, the first thing most people want is a shell. The README gives two routes. From the RouterOS terminal, run the shell command:

/system/shell

The shorthand /sh does the same thing. Over the network, the devel account is the one to use, with the admin password:

ssh devel@<router-ip>

Inside that shell, on x86, you can switch between CHR and x86 mode. This matters because the two modes have different licensing behaviour in stock RouterOS, and the patch makes the switch a shell command:

keygen chr
keygen x86

If you want something to run at boot, the README documents an rc.local file at /rw/disk/rc.local. The comment in its example states the script runs before the RouterOS loader starts. You confirm it ran by reading the boot log:

cat /ram/startup.catlog | grep 'Hello'

That grep is the only documented way to verify the script executed, so keep the echo line in your script if you want that check to work.

Container mode and the reboot you cannot skip

Enabling containers on RouterOS normally means a device-mode change and a reboot. The README documents the sequence, and it is worth reading carefully because the second command has to run in a new terminal:

/system/device-mode/update container=yes
/system/shell cmd="reboot -f"

The note that the reboot must be issued from a separate terminal is not decoration. The first command changes device mode and RouterOS will not apply it until the router restarts, so if you run both lines in one session you may lose the session before the second command lands. The README does not say what happens if you do, and it does not describe a recovery path.

There is a second constraint buried in the feature guide: all the features it lists require option.npk to be installed first. Container mode is in that list. So the order is fixed. Licence package, then device mode, then reboot, then containers. If you try to enable container mode on a stock RouterOS build, you are on your own, because the README does not cover that case.

Where this breaks, and when it is the wrong tool

The licence grant is the sharpest limitation. The README says installing option.npk automatically grants the highest-level licence. That means the licence is not bound to a serial number or an account in any way the documentation describes. Anyone who can install packages on the router gets the same result, and there is no documented way to tell a patched router from a licensed one from the outside. If your environment requires provable licence compliance, this project is disqualified before you evaluate anything else.

Architecture coverage is the second boundary. The project handles x86 and arm64. Everything else, arm, mipsbe, mmips, ppc and smips, is on the other site and requires sponsorship. That is not a small gap. A large share of MikroTik's shipping hardware is arm or mipsbe, so the free path covers CHR and x86 installs, which is a lab-shaped footprint rather than a fleet-shaped one.

The upgrade path is the third problem. The releases track specific RouterOS versions, and there is nothing in the README about what happens when you upgrade a patched router to a stock build, or whether option.npk survives an upgrade. The README does not document rollback either. If you patch a router and then upgrade it, you are testing an undocumented transition. The cloud services table lists system/package/update/install as the online upgrade command, which is the same command a stock router uses, so the patched state and the upgrade path are not isolated from each other.

Finally, the licence is WTFPL. That is permissive in the extreme, and it comes with no warranty of any kind. For a lab that is fine. For anything with a support contract attached, it is not.

How it compares with a CHR licence or a plain RouterOS install

The obvious alternative is a legitimate CHR licence. MikroTik sells CHR as a software instance, and a licensed CHR gives you the same x86 virtual machine without any package modification. The difference in approach is where the trust sits. A licensed CHR validates against MikroTik's activation, so upgrades, cloud services and support all behave as documented. MikroTikPatch replaces the validation step, which is exactly why the README restricts it to testing.

The second alternative is simply running RouterOS on real hardware with the licence it shipped with. That costs more per unit, and it does not give you the CHR to x86 mode switch or the devel shell, but it removes every question about package signatures and upgrade behaviour. If your goal is to learn RouterOS rather than to test a patched image, the official CHR trial and the manual at manual.mikrotik.com cover the same ground with none of the risk.

The third comparison is the sibling project at routeros.ltd. It covers the architectures this one does not, but it requires sponsorship and offers online custom brand package creation. So the split is not free versus paid in a simple sense. It is free for x86 and arm64 with a patch you apply yourself, versus sponsorship for the other architectures with a hosted service. Pick based on your hardware, not on price.

Maintenance, licence and what to check before you rely on it

The repository is not archived, and the last push was on 2026-09-23. Releases track RouterOS versions closely: 7.25beta5 and 7.25beta5-arm64 were published on 2026-09-22, and 6.49.22 on the same day. That cadence means the project follows RouterOS releases rather than sitting on a fixed fork, which is what you want if you are testing against current firmware. It also means the useful version is the one matching your RouterOS build, and an older release will not help you on a newer router.

The upgrade cost is real. Because each release is tied to a RouterOS version, staying current means re-downloading and re-applying whenever you move RouterOS forward. There is no documented in-place update mechanism for the patch itself. You also inherit the risk that a RouterOS change to package verification breaks the patch, and the README gives no compatibility matrix beyond the release names.

On licensing, the code is under WTFPL, which places almost no conditions on reuse or redistribution. That applies to the project's own code. It does not grant you anything with respect to RouterOS itself, which remains MikroTik's commercial product under MikroTik's terms. The README's testing-only notice is the project's own statement of that boundary, and it is the line to hold if you are deciding whether this fits your environment. This is not legal advice; if the licence question matters to your organisation, ask someone qualified.

Before you build anything on it, confirm the release name matches your RouterOS version and architecture exactly, confirm you can reach the router after option.npk is installed, and confirm you have a stock image to fall back to. The README does not document a rollback, so that fallback is your responsibility, not the project's.

Editorial conclusion

Adopt elseif/MikroTikPatch only if you are building throwaway RouterOS labs on x86 or arm64 and already have a way to rebuild the router afterwards. Do not adopt it for production routers, for arm, mipsbe, mmips, ppc or smips hardware, or where the WTFPL licence and the absence of any warranty are a problem for your organisation. Before you commit, verify three things: that a release exists for your exact RouterOS version and architecture, that your router can reach the network after the option.npk install, and that you have a documented way back to a stock image, because the README does not describe one.

Frequently asked questions

Official sources

1. elseif/MikroTikPatch on GitHub
2. License: WTFPL
3. Project website
4. README
5. Releases