If the eFuse is truly blown (indicated by the specific register readout), here is the reality:

MediaTek has a built-in authentication mechanism called SLA (Secure Download Agent Authentication) and DAA (Download Agent Authentication). The eFuse 0x146 forces the BROM to demand a cryptographically signed DA.

The Fix: Tools like MTK Client (Python tool by bkerler) and UnlockTool have developed methods to bypass this authentication using a brom payload that ignores the eFuse check.

Best Steps for MTK Client (Free & Open Source):

Note: This works best on pre-2023 chips (MT6765, Helio G85). Newer Dimensity chips have patched this bypass.

Look for markings on the main chip (e.g., RK3566, RK3588, Allwinner, Amlogic). Different vendors use different error codes.