Anycubic Kobra X (K4Pro)

General

• Software base: KlipperC++
• Supported by Rinkhals: No (Blocked by RSA Signature)
• Firmware SWU password: rCRgz7RMqOyAYCaQ7TgkmPPDyo3LIEqtuEhv8ZEASa7rfwP3p2XoyQZA8IYYV8W3
• MCU SWU password: U2FsdGVkX19deTfqpXHZnB5GeyQ/dtlbHjkUnwgCi+w=
• Ex/Im password: 2YLVrATRvUEnMeXk6Vtc7qxfzYM4TJzrLnEBma8zpUKeGtseGWqp4LXs7e8KeU2u
• SSH root password: rockchip

Software Architecture

The Kobra X (K4 software base) represents a complete overhaul compared to the K3 series. It moves away from the Go-based "GoKlipper" stack (K3SysUi, gklib, gkapi) and introduces a C++ implementation of Klipper.

The core system processes are: - avata_main: The main control logic (C++ Klipper port). - avata_ui: The user interface. - avata_video: The cam control logic.

Firmware Security & RSA Barrier

The Kobra X introduces mandatory RSA Signature Verification. The installer validates the update package (setup.tar.gz) against a public key (/etc/ssl/public_key.pem) using OpenSSL.

Because the setup.tar.gz must be signed by Anycubic's private key to generate a valid setup.sig file, custom firmware injection is currently impossible through standard update methods.

Potential Bypass and Risks

Future custom firmware installation will require a vulnerability to bypass this check, such as:

1. Physical Access: Using Serial to gain root access and manually overwrite the public key.
2. Software Vulnerabilities: Finding a flaw in the avata_main or avata_ui processes to achieve arbitrary code execution.

Stability and Update Warnings

If a bypass is found and a custom firmware is installed, be aware of the following:

• OTA Updates: Over-the-air updates will no longer function.
• Manual Updates: Installing an official firmware file will overwrite the custom firmware and could lead to a system mismatch.
• Brick Risk: Mixing official update components with modified system files carries a significant risk of "bricking" the printer, potentially making it unbootable (Recoverable by Serial).