How to root-cause Wi‑Fi chip stops after 30 minutes

You are executing automated tests against a Wi-Fi chip. Initially the chip transmits as expected, but after roughly 30 minutes it ceases transmitting (no signal is detected). You may assume that the test, firmware, and measurement configuration can all be changed. Outline a hands-on, step-by-step root cause investigation procedure. Which data would you gather, which hypotheses would you rank first, and which experiments would you perform to isolate the cause? Overview: This question assesses troubleshooting and diagnostic ability for embedded wireless systems, with emphasis on firmware behavior, testbed instrumentation, and measurement analysis.