Fix "authentication error" GameBoy clone everdrive

[MartialBlot]

Hello everyone ,

If you've ever purchased a cheap EverDrive clone for Game Boy from platforms like AliExpress or Amazon, you might have encountered the dreaded "Authentication Error" when trying to update the cartridge with an official firmware.

I personally own a Game Boy GB PRO+ Rev C (2023), but let’s be honest—these cartridges often have similar designs and components with minor variations, making identification tricky.

The purpose of this guide is to gather all relevant information and provide a working solution. I want to emphasize that this tutorial is for repairing your own cartridge, and I do not encourage ROM piracy. Make sure you own the games you’re working with.

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The Problem​

From various forums, it appears this error happens when an official firmware detects the cartridge as a clone. The update process corrupts the NOR flash chip (M29W640FT), resulting in a boot loop with "Authentication Error."

Fixing this issue can be both a fun technical challenge and a way to save a low-cost product that still works.

Disclaimer: This tutorial requires intermediate technical skills. I am not responsible for any damage you may cause. Proceed at your own risk!

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Why Not Use the SD Card?​

Unfortunately, the cartridge BIOS startup sequence prevents access to the SD card before the error appears. Injecting a script or using the SD card to restore the BIOS isn't possible in this state.

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The Solution: Reprogram the Flash Chip​

Since the issue lies with the M29W640FT flash chip, reprogramming it is the only reliable solution. Here's how to do it:

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Step 1: Desolder the Flash Chip​

You’ll need a heat gun (hot air rework station) and some flux to safely desolder the chip.
Take your time and be careful not to damage nearby components.

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Step 2: Programming the M29W640FT​

Initially, I tried programming the chip using an Arduino MEGA with a TSOP-48 DIP48 adapter, but this approach failed due to the chip’s complexity.

Instead, I opted for a T48 Programmer with the ADP_F48_EX-1 adapter, and it worked flawlessly using the Xgpro software.

Here’s how to proceed:

• Select the correct chip in Xgpro:
  • Choose M29W640FT from the chip list.
• Connect the T48 programmer:

Install the adapter and insert the desoldered chip.

• Load the modified BIOS file at the correct address:
  • The BIOS fix file is available on attach files :
    (credit to user marv12345 from elotrolado forum for disabling the error). The version seems more superior to the original one in my case.
  • The M29W640FT chip has 8MB of flash memory (64 Mbits), covering addresses from 0x000000 to 0x7FFFFF.
  • The modified BIOS file is 32KB and must be written to the range 0x7F8000 to 0x7FFFFF.
  • In Xgpro, configure the file loading as follows:
  • From File Start Address: 00000 > To Buffer Start Address: 7F8000
    
    
    
    
• Finally push PROG button to flash your chip

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Step 3: Resolder the Chip​

Once the chip is successfully programmed, it’s time to put it back in place.

• Clean the PCB pads:
  • Use desoldering braid to remove old solder residue.
  • Inspect the area with a magnifying glass.
• Prepare the chip for soldering:
  • Apply a small amount of solder to each pad and align the chip correctly (the pin 1 marker is critical!).
• Solder the chip:
  • You can use either a hot air gun or a fine-tipped soldering iron with flux.
  • Double-check the alignment and connections to ensure there are no shorts.
• Inspect everything carefully:

Verify all pins are properly soldered and clean up any excess solder.

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Step 4: Test the Cartridge​

Once everything is reassembled, pop the cartridge into your Game Boy and test it. If everything was done correctly, the "Authentication Error" should be gone, and the cartridge will boot normally!

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Final Notes​

• If you accidentally damage the chip during desoldering or programming, don’t worry replacement M29W640FT chips are readily available on AliExpress at a reasonable price.
• Always work with good tools: flux, desoldering braid, and a proper programmer make all the difference.

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Summary of Tools and Steps​

Tools Required:

• Heat gun (or hot air station)
• Flux and desoldering braid
• T48 Programmer with ADP_F48_EX-1 adapter
• Xgpro software
• Magnifying glass or microscope

Steps:

1. Desolder the M29W640FT flash chip.
2. Program the chip with the BIOS fix (write to 0x7F8000 - 0x7FFFFF).
3. Resolder the chip carefully.
4. Test the cartridge.

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Conclusion​

And that’s it! By following this guide, you’ll successfully repair your EverDrive clone and restore its functionality.

If you found this tutorial helpful or have any questions, feel free to share your experiences below. Let’s keep these cheap little cartridges alive!

Happy repairing, and good luck!

 

[nvienot]

Super interesting, thank you for sharing!

 

[Jayro]

Can I just use my GBxCart RW to flash the new BIOS over?

 

[MartialBlot]

Can I just use my GBxCart RW to flash the new BIOS over?

I Jayro,
I don’t believe the GBxCart RW supports flashing NOR Flash chips like the M29W640FT. The GBxCart RW is designed for working with EEPROMs and other memory types but not typically for NOR Flash. These chips usually require specific programming sequences, which generally involve desoldering the chip first. I do not own one, so I have not tested it myself. If a hack like this ever exists, I’d be curious to see the steps.

 

[Jayro]

I Jayro,
I don’t believe the GBxCart RW supports flashing NOR Flash chips like the M29W640FT. The GBxCart RW is designed for working with EEPROMs and other memory types but not typically for NOR Flash. These chips usually require specific programming sequences, which generally involve desoldering the chip first. I do not own one, so I have not tested it myself. If a hack like this ever exists, I’d be curious to see the steps.

I tested mine on the GBxCart RW, and it can sadly only see the 32KB ROM, but isn't flashable. Read-only. So I at least have a good dump of the installed one.

 

[SylverReZ]

There's a new way of un-bricking EverDrive-GB clones with the use of a tool that communicates with the on-board CPLD to bypass the clone checks. It requires either a DMG or CGB Game Boy system as the method to do so involves hotswapping cartridges; one cartridge (usually an AliExpress bootleg or those GB Smart carts with the ROM flashed) with the un-bricker ROM, and your clone EverDrive.

P.S. only older clones are known to work with this method and not the current newer ones.

Full write-up of how it was possible: https://bitwise.bperki.com/2026/03/06/fixing-an-everdrive-clone-part-3/

 

[Jayro]

There's a new way of un-bricking EverDrive-GB clones with the use of a tool that communicates with the on-board CPLD to write the fixed firmware still in the flash memory without the clone checks. It requires either a DMG or CGB Game Boy system as the method to do so involves hotswapping cartridges; one cartridge (usually an AliExpress bootleg or those GB Smart carts with the ROM flashed) with the un-bricker ROM, and your clone EverDrive.

Full write-up of how it was possible: https://bitwise.bperki.com/2026/03/06/fixing-an-everdrive-clone-part-3/

FRONT PAGE NEWS-WORTHY!

 

[SylverReZ]

FRONT PAGE NEWS-WORTHY!

EDIT: It doesn't work with the "Low Power Consumption" versions,. Just re-tested it and nope, no changes made to the flash at all. So they were right that it only works with the older clones which use an LDO regulator.

I agree that this should be made newsworthy as there's not a lot of people talking about it. No more writing to the flash chip with desoldering and a dedicated programmer, this takes the cake for being a very useful utility.

 

[hippy dave]

Glad it worked for you. The linked page mentions it only works on older clones, as newer ones cause the GB to reboot when plugged in. Worth mentioning before anyone else deliberately bricks their cart to test.

 

[SylverReZ]

Linked page mentions it only works on older clones, as newer ones cause the GB to reboot when plugged in. Worth mentioning before anyone else deliberately bricks their cart to test.

Did not see that, thanks. Yes, the earlier ones seem to be based around the EDGB v1 design over the others, whereas the later clones claim to be "power saving" and include switching regulators or level shifters and have titles like "GB Pro+" or "Game Color", but they both have Altera Max-II CPLDs.

 

[tech3475]

Glad it worked for you. The linked page mentions it only works on older clones, as newer ones cause the GB to reboot when plugged in. Worth mentioning before anyone else deliberately bricks their cart to test.

Depending on why this happens, there could be potential workarounds.

For example, if it's cause by the reset line on the cart maybe temporarily blocking this (tape? custom FPGA core? custom PCB? etc.).

 

[hippy dave]

Depending on why this happens, there could be potential workarounds.

For example, if it's cause by the reset line on the cart maybe temporarily blocking this (tape? custom FPGA core? custom PCB? etc.).

The link (am I the only one who read it?) says it's because of a spike in power drain.

 

[tech3475]

The link (am I the only one who read it?) says it's because of a spike in power drain.

Sorry, thought you were referring to the OP for some reason and couldn't see a link until I scrolled down afterwards (time for coffee I think).

Still, I wonder if there may be some workaround using something else.

Although now that I think about it, I wonder if those carts could be potentially damaging hardware if they're drawing that much power?

 

[xy1154]

There's a new way of un-bricking EverDrive-GB clones with the use of a tool that communicates with the on-board CPLD to bypass the clone checks. It requires either a DMG or CGB Game Boy system as the method to do so involves hotswapping cartridges; one cartridge (usually an AliExpress bootleg or those GB Smart carts with the ROM flashed) with the un-bricker ROM, and your clone EverDrive.

P.S. only older clones are known to work with this method and not the current newer ones.

Full write-up of how it was possible: https://bitwise.bperki.com/2026/03/06/fixing-an-everdrive-clone-part-3/

Unfortunately after several attempts on both stock DMG and IPS modded CGB (and even GBASP, out of desperation), the method does not work with early "Jack DIY" clone either. I flashed EverDriveRescue.gb onto a few rewrittable cartridges ranging from PokeMon repro (via FlashGBx) to "chis" (an open source solution). Among my failed attempts, some would trigger a reboot sequence, some led to an odd error message "0x5d", while others froze on "Insert Bricked Everdrive clone" screen. Only on very rare occasions when it did allow the bricked cart to boot, but then the authentication error message persisted.