G4 · guide
How to flash a BIOS chip safely
Writing firmware can make a board unbootable. Work only on your own devices, keep the original dump, and if you are unsure — ask a repair shop.
What you need
- An SPI programmer: CH341A (cheap, fine for most 25-series chips), XGecu T48 or RT809H (more reliable, more chips).
- A SOIC-8 test clip, or a hot-air station to remove the chip.
- A 1.8 V adapter if the chip is a 1.8 V part.
- Programmer software (for CH341A: NeoProgrammer or AsProgrammer).
Checklist
- Identify the chip. Read the marking: W25Q64, MX25L12835, GD25B127… Check its voltage in the datasheet — chips like W25Q…FW or MX25U… run at 1.8 V and need the adapter.
- Power off completely. Unplug the charger and disconnect the battery and CMOS battery.
- Read the chip twice and compare both files (same checksum). Save this backup somewhere safe.
- Pick the right dump. Same board number and revision; the file size must equal the chip size (25Q64 = 8 MB, 25Q128 = 16 MB, 25Q256 = 32 MB).
- Move unique data if needed: serial number, UUID, LAN MAC address and the embedded Windows key live in the BIOS region. Copy them from your backup with the vendor DMI tool or a hex editor.
- Erase, write, verify. Let the software verify after writing, then reconnect power and test.
Words you will see in file names
| Term | Meaning |
|---|---|
ME clean, ME RST | The Intel Management Engine region is reset to a clean state. Used when a board does not start, shuts down after ~30 minutes or behaves oddly after a failed update. |
EC, KBC | Embedded controller firmware (keyboard, power button, charging). Some boards keep it in a separate chip (IT8xxx, ENE KB9012) — it needs its own dump. |
Unlock, no password | BIOS with the supervisor password removed — only for your own device. |
Tested, OK | The uploader says it worked on their board. Still verify board number and revision. |
.cap | ASUS capsule file. Remove the first 0x800 bytes before writing it with a programmer. |