R0rt1z2/kaeru ? reverse-engineered prompt

Build me a tool for MediaTek devices that takes a Little Kernel bootloader image and patches it so I can run a custom ARMv7 payload during boot.

I want it to be practical for real device research, so it should build cleanly, generate a patched bootloader image I can flash, and support device specific offsets and addresses. Please make the code and build process easy to follow, and include a clear way to customize the payload for a new device when needed.

If there are parts that depend on current tooling or library details, feel free to look up the latest docs online and make sensible choices. I also want helpful output during the build so I can tell what image was patched and what settings were used.

Please keep in mind this is for advanced bootloader debugging and customization, not a beginner friendly toy, so focus on reliability and clarity.