I'm Piyush, an experienced embedded systems engineer specializing in firmware development. I have a deep understanding of the Android operating system and have previously created custom images that fully incorporate client branding. In fact, in one project, I successfully integrated important industrial protocols into a Raspberry Pi setup, a task that involved configuring and optimizing the system to run specialized software. Adapting this experience to develop your customized Android rom for both Banana Pi m4 zero and Raspberry Pi 4b would align impeccably with my expertise.
Moreover, user accessibility is essential to any product's success. I understand your requirement for a uniquely tailored system that allows users to exclusively set wifi settings without access to other Android functionality. This aspect actually aligns perfectly with the kind of projects I have successfully completed earlier. Particularly, your request for enabling wifi credential input over Bluetooth signals resonates greatly with my experience in utilizing wireless communications in embedded systems efficiently.
In conclusion, I believe I am best equipped to fulfill your project requirements by leveraging my extensive knowledge of Android systems and proven capabilities in creating customized firmware.