ASUS Zenbook Pro Duo UX8402ZA BIOS
Hello everyone,
I recently bought a non-working Asus Zenbook Pro Duo OLED UX8402ZA that was listed for parts only. The seller mentioned that it had no display output but that the charging lights worked.
When the laptop arrived (without a charger and SSD), I connected a charger and confirmed with a multimeter that it was charging the battery. However, when I tried to power it on, only the backlight of the secondary display came on. There was no image, and it didn’t boot into the BIOS.
I decided to try flashing a new BIOS, but since I didn’t want to desolder the chip, I bought a CH341A programmer, a set of clamps and accessories, and a few spare WSON8 Winbond chips to experiment with. I also ordered a WSON8 6x5mm pogo-pin adapter that lets you read and write directly to the BIOS chip on the motherboard.
After a few attempts, I managed to read the BIOS chip successfully and saved a backup . I then spent several hours researching and experimenting. Using HxD, I extracted the BIOS file from the official Asus update executable and tried to modify it to the correct 16,384 KB size. However, I ended up with a file that was a few kilobytes larger and had data shifted compared to the original. I even tried generating a BIOS file with ChatGPT, but that didn’t work as expected either.
After numerous trials and errors, I decided to proceed with flashing the BIOS. I erased the chip and started programming it, but both NeoProgrammer and ASProgrammer kept crashing due to poor contact between the adapter pins and the chip. I tried more than 50 times. I could flash my spare chips successfully, but not the one on the motherboard.
As a last resort, I used a BIOS file shared by @volinakis in this thread. After 3–4 tries (and probably holding the adapter just right), the flash succeeded. The laptop finally booted into the BIOS and came back to life!
However, since this BIOS was for a slightly different model number UX8402ZE (mine UX8402ZA has no dedicated GPU and less RAM), several issues appeared:
My questions are:
I’d greatly appreciate any guidance or advice. This is my first time doing something like this, and there’s no one nearby who’s familiar with BIOS repair or programming.
Thank you for your time and help!
I recently bought a non-working Asus Zenbook Pro Duo OLED UX8402ZA that was listed for parts only. The seller mentioned that it had no display output but that the charging lights worked.
When the laptop arrived (without a charger and SSD), I connected a charger and confirmed with a multimeter that it was charging the battery. However, when I tried to power it on, only the backlight of the secondary display came on. There was no image, and it didn’t boot into the BIOS.
I decided to try flashing a new BIOS, but since I didn’t want to desolder the chip, I bought a CH341A programmer, a set of clamps and accessories, and a few spare WSON8 Winbond chips to experiment with. I also ordered a WSON8 6x5mm pogo-pin adapter that lets you read and write directly to the BIOS chip on the motherboard.
After a few attempts, I managed to read the BIOS chip successfully and saved a backup . I then spent several hours researching and experimenting. Using HxD, I extracted the BIOS file from the official Asus update executable and tried to modify it to the correct 16,384 KB size. However, I ended up with a file that was a few kilobytes larger and had data shifted compared to the original. I even tried generating a BIOS file with ChatGPT, but that didn’t work as expected either.
After numerous trials and errors, I decided to proceed with flashing the BIOS. I erased the chip and started programming it, but both NeoProgrammer and ASProgrammer kept crashing due to poor contact between the adapter pins and the chip. I tried more than 50 times. I could flash my spare chips successfully, but not the one on the motherboard.
As a last resort, I used a BIOS file shared by @volinakis in this thread. After 3–4 tries (and probably holding the adapter just right), the flash succeeded. The laptop finally booted into the BIOS and came back to life!
However, since this BIOS was for a slightly different model number UX8402ZE (mine UX8402ZA has no dedicated GPU and less RAM), several issues appeared:
- The serial number is missing in both BIOS and Windows.
- The keyboard backlight doesn’t work.
- The secondary screen only turns on after pressing its button twice.
- The fans spin loudly for a moment, then go silent.
- The ASUS software for the second display is not working, and I can’t adjust its brightness.
- The HDMI is not recognizing a connected monitor.
My questions are:
- Is it possible to flash the official ASUS BIOS executable (for UX8402ZA, version 306) without risking bricking the laptop? The currently installed BIOS is version 307 for UX8402ZE.
- Can I extract my serial number, Windows key, and other system data from the original BIOS backup and inject them into a modded file that can be safely flashed via Windows or the built-in BIOS update utility?
I’d greatly appreciate any guidance or advice. This is my first time doing something like this, and there’s no one nearby who’s familiar with BIOS repair or programming.
Thank you for your time and help!
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