Devices marked as "1662 patched" (or similar later versions) have updated bootrom or bootloader security that closes these hardware exploits. This means they can no longer be unlocked through "simpler" methods like the widely used S1 Unlock Tool . 2. Unlocking and Relocking Challenges Status for "1662 Patched" Devices Bootloader Unlock Allowed
It means the unlocking process is not just a software flag. It is a cryptographic challenge. You request a token from the manufacturer’s server. That token is signed with a unique key tied to your Device ID (SN/IMEI). The Secure Enclave verifies this signature offline. If the token doesn't match the hardware hash, the device refuses to unlock.
The specific process for the 1662 model highlights the delicate nature of flashing protocols. Unlike generic ADB commands, Sony devices require the use of the Flashtool utility (Emma) or the NewFlasher command-line tool. The procedure typically involves flashing the bootloader and loader SIN files.
Relocking is often necessary to get banking apps working or to return to stock for warranty service.
Once the tool reports success, boot into fastboot mode. Confirm Unlock: Verify by running fastboot oem device-info . Relocking the Bootloader (Reversing the Process)
If you receive a "device is corrupted" message after unlocking a patched device, this is often normal, as described in 2026 Fairphone 3 forum discussions . It indicates the bootloader is warning you that the software signature has changed.
Historically, developers bypassed this chain by targeting the secondary bootloader (often the Little Kernel or LK layer). Methods involved:
Some specialized tools (like paid S1 server credits) occasionally find new exploits for patched devices, though availability is inconsistent.
Q: What is the SE bootloader? A: The SE bootloader is a custom bootloader developed by Sony Ericsson for their devices.
As of the latest HyperOS and Android 14 updates, the 1662 patch prevents almost all "deep-test" exploits. You cannot use older Mi Unlock versions (like 3.x or 4.x) because the server rejects them with a 1662 timeout.