What they did
The author, cavaleiro-ai, wrote a Claude Code skill that works on an Android phone plugged in over USB. Before touching anything it asks how far to go, from read-only diagnosis through reversible tweaks (animations, background scans, app compilation), app cleanup, root and overclocking, plus an optional switch to a custom ROM. It saves the old values, measures before and after each change and undoes what does not help. It also has an optional flow that picks a RetroArch build and PCSX ReARMed core for the phone's chip, checks and pushes a game file the owner supplies, and measures frame rate. The author ran it on a Moto G 2014 with 1 GB of RAM, moving it from Android 6.0 to LineageOS 17.1, and published it as a plugin.
How it went
On the Moto G, WhatsApp opened in 2.05 s instead of 3.46 s and Telegram in 3.36 s instead of 4.64 s. Resident Evil 3 ran at 59.89 FPS in an automated 3D scene with a worst frame gap of 33 ms. Sound and hands-on play were not checked. The author says this is the only device it has really been run on: root, performance mode and overclocking were never executed, and the emulator was only tried on 32-bit with one game. Full logs, including the failures, are in the repo's case studies.
Worth knowing
Unlocking the bootloader or flashing a ROM wipes the phone, may void the warranty and can break banking apps. The skill asks for an explicit confirmation before deleting data. It will not bypass screen locks, FRP or carrier locks, change IMEIs, or download games or BIOS files. Docs are in Portuguese, but it replies in your language. Anything typed in the session goes to the model, so enter passwords on the phone itself.