Unlike traditional unlocking methods where a unique key is requested from the manufacturer to run fastboot oem unlock, the Nokia 3.4 exploit relies on a loophole in the flashing order.
The device's bootloader logic contains a vulnerability where, if the boot_a partition is flashed via Fastboot while the device is in a specific state (often related to blankflash or EDL mode protocols transitioned to Fastboot), the Bootloader Verification is not immediately enforced or is bypassed, allowing an unsigned or modified image to boot. nokia 3.4 unlock bootloader
Note: This method is often volatile and carries a high risk of hard-bricking the device (rendering it unrecoverable via standard software means). Unlike traditional unlocking methods where a unique key
If you flash an incorrect bootloader image, the Nokia 3.4 can become a hard brick (no power, no LED, not recognized by PC). Recovery from hard brick requires an EDL cable and authorized Qualcomm programmer – nearly impossible for normal users. Result: No public, working exploit for Nokia 3
To avoid bricking: