Silicon Labs EFR32 BLE wireless MCU uses flash protection. EFR32 decryption unlocks it to recover firmware.

EFR32 Protection:
- Debug access port is locked.
- Flash readback is prevented.
- Software debug interface is disabled.
- Device information page is protected.

EFR32 Decryption Methods:
1. Voltage Glitching: glitch VDD during debug lock check.
2. Clock Glitching: fault debug controller.
3. Decapsulation: read silicon die directly.
4. Side-Channel: power analysis during access.

EFR32 is used in BLE beacons, smart home, and wearable devices.