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PreLoader vs BROM on MediaTek: difference, ports and entering the right mode

Updated 2026-11-04 · Русская версия

MediaTek has two close but different service modes: BROM and PreLoader. They are often confused, yet which one the phone entered decides whether the operation succeeds.

What BROM is

BROM (Boot ROM) is an unchangeable program inside the MediaTek processor itself. It runs first, before any firmware on the phone. It is the lowest and most powerful service mode: you can flash the phone even when its memory is empty or corrupted.

What PreLoader is

PreLoader is the first bootloader written on the phone memory. It runs right after BROM on a normal power-on. PreLoader is available only briefly at start and does not suit every operation: if the memory is damaged, PreLoader may not run at all.

Telling them apart by port

If you see PreLoader USB VCOM, the phone entered PreLoader. Many operations need MediaTek USB Port — BROM.

Why BROM is more reliable

• works even with empty or corrupted memory;
• gives full access for flashing and repair;
• does not depend on the phone bootloader state.

So for serious operations (flashing, recovery, some FRP) you aim to enter BROM.

How to enter BROM

1. Power the phone off fully.
2. Launch the tool, pick the model and operation.
3. Press Start.
4. Hold both volume keys (one on some models) and connect the cable.
5. Hold until MediaTek USB Port appears.

If PreLoader appears instead, start from a fully off phone and hold the keys longer. Some models need a test point.

When PreLoader is enough

Some read-info and simple tasks work via PreLoader. But if the tool errors or demands BROM, do not force it through PreLoader — enter BROM properly.

Protected BROM on new chips

On new MediaTek (recent Helio G, Dimensity) the BROM is protected (SLA/DAA). You can enter it, but writing needs a service tool with a bypass. SP Flash Tool with a plain DA then errors with 2005 and similar.

When each mode

Common entry mistakes

• connecting the phone before pressing Start — ending in PreLoader or nowhere;
• not holding the keys long enough;
• not starting from a fully off phone;
• using a charging cable.

How it looks in the log

A service tool log shows which mode the phone entered, with lines mentioning BROM or PreLoader and the port VID/PID. If the tool waits for BROM while the phone entered PreLoader, the operation will not start. Learn to read these lines.

Real-world example

A MediaTek phone would not flash: the log showed it entering PreLoader, not BROM. The technician powered it off fully and held the keys longer — MediaTek USB Port appeared and the flash completed.

Glossary

• BROM — boot ROM in the chip, the lowest mode.
• PreLoader — first bootloader on the phone memory.
• VCOM — MediaTek virtual COM port driver.
• SLA/DAA — BROM protection.

Which tool fits

For BROM work: TSM Tool Pro rental, UnlockTool rental, Cheetah Tool Pro rental. Check the model and operation before paying.

Bottom line

BROM is the lowest and most reliable MediaTek mode, PreLoader is higher and not for every task. For flashing, enter BROM: power off, press Start and hold the keys until MediaTek USB Port appears.

Link to error 2005

If the phone enters BROM but SP Flash Tool gives error 2005, it is not the mode but BROM protection: you need a bypass in a service tool. If you do not see MediaTek USB Port at all, first get into BROM, then deal with protection. Do not confuse these two problems.

Working efficiently

Make it a habit to read the port name in Device Manager before each operation. One check — BROM or PreLoader — saves many failed attempts.

Short summary of differences

Intake note

Before quoting a MediaTek flash, confirm you can reach BROM on that model. If only PreLoader appears and the operation needs BROM, you may need a test point, which changes the time and the price.

FAQ

Related guides

• BROM error 2005
• MediaTek VCOM driver