Cross-Vendor State Observability: An Evidence-Bounded Case Study of Mobile and Automotive Systems

Cross-Vendor State Observability: An Evidence-Bounded Case Study of Mobile and Automotive Systems presents an independent systems investigation into how state is represented, transformed, and observed across distinct software, hardware, and diagnostic boundaries. The research brings together two independently developed investigations involving Apple mobile devices and a Jeep Compass/Uconnect environment. What began as separate examinations of image-processing behavior, device restoration, application lifecycle events, and automotive diagnostics evolved into a broader study of state continuity, representation fidelity, and the limits of causal attribution. The manuscript documents the experimental progression from digital watermarking and image transformations to extreme-geometry JPEG testing, alongside controlled firmware restoration observations. The automotive investigation contributes a separate body of service records, diagnostic artifacts, firmware observations, and interface behavior. Rather than presuming a common defect across the investigated systems, the study develops a framework for distinguishing observable behavior from internal state, experimental outcomes from causal mechanisms, and documented evidence from unresolved hypotheses. The publication includes technical methods, implementation excerpts, mathematical formulations, experimental results, diagnostic interpretations, an evidence reference register, and supporting appendices. This work is part of the independent Silicon Gremlin research program, emphasizing reproducible investigation, evidence provenance, and explicitly bounded technical conclusions.