Brom Disabled By Efuse 0x146 May 2026

eFuses (Electronic Fuses) are one-time programmable memory bits. They are used to store permanent configuration data, such as:

Once an eFuse is "blown" (set from 0 to 1), it cannot be reverted.

The error is widespread on:

In short, any MediaTek device released after 2021 with secure boot v2 or higher has a high probability of blowing the debug eFuse during the first boot.

Based on reverse-engineered Boot ROM dumps, 0x146 corresponds to a single eFuse bit that disables the normal BROM boot path. When blown: brom disabled by efuse 0x146

MediaTek provides authorized download agents (auth DA files) to OEMs. These files contain cryptographic keys that match the eFuse values. If you obtain the correct auth file for your exact device model and CPU, you can load it in SP Flash Tool and bypass the error.

Practical step: In SP Flash Tool, go to Options > Authentication File and load the corresponding auth_sv5.auth file before connecting the device. Once an eFuse is "blown" (set from 0

Let us parse the error message piece by piece:

If the BROM is dead but the eMMC is accessible via an external programmer (direct eMMC connection): In short, any MediaTek device released after 2021

Caution: Secure boot will still check signatures. You can only write signed firmware.

On some devices, shorting specific test points on the motherboard (e.g., KCOL0 to KROW0 or CMD to CLK on eMMC) can force the SoC to bypass the eFuse check temporarily. This is advanced and requires disassembly. Even then, success is not guaranteed for error 0x146.