Xdelta — Patcher Android

Patching on Android has evolved from a niche workaround to a seamless experience. With tools like UniPatcher, you can take a raw ROM, apply a massive fan-made expansion, and be playing in your favorite emulator in under a minute.

For patch creation, stick to a PC. For patch application , Android is perfectly capable.

If you don't want to install an app, many users utilize web-based tools (like Marc Robledo’s Online Rom Patcher) through a mobile browser. These work surprisingly well on Android for quick fixes. How to Apply a Patch on Android (Step-by-Step)

However, for the foreseeable future, of offline, privacy-respecting Xdelta patching on Android.