Magento Luma Module Not Working in Hyvä: The Diagnostic Order
Your Luma extension worked yesterday on Magento Blank. Today on Hyvä it renders nothing, or worse, breaks the page silently with no console error. The fix is not "reinstall the module" or "flush cache". There is a diagnostic order, four checks in sequence, each with a distinct DevTools signal, that resolves 95% of Luma-to-Hyvä incompatibilities. This guide walks the order using real modules we have debugged (Mageplaza, Amasty, MGS) on Magento 2.4.4-2.4.9 production sites. Each step has the actual symptom, the actual signal, and the actual fix, not a generic compatibility checklist.
