| Issue | Symptom | Fix | | :--- | :--- | :--- | | | Device stuck at preloader, no USB detection | Check memory_para in cust file; reflash preloader | | Modem panic | “No service” or baseband unknown | Restore NVRAM from backup; rewrite IMEI using SN Writer | | TEE mismatch | Fingerprint/DRM fails after OTA | Ensure tee partition matches kernel driver version | | Logo corruption | White screen during boot | Reflash logo.bin using logo_resize tool |
Closed baseband and secure-world firmware are the riskiest parts: they run with high privileges and little transparency. For threat-conscious users, prefer devices with documented firmware practices or manufacturers that publish kernel and firmware sources on time. mt6739 firmware