How do you remove the "FX" from Arduboy FX

Like the title - say I wanted my Arduboy FX wanted to function as a single cart Arduboy, what would I need to do?

Removing the mod chip, flashing stock bootloader comes to my mind.
Is this correct and is there anything else?

Assuming this is correct, where do I get the stock bootloader? And would I write it to Arduboy just like we write the FX bootloader?

Not sure what you mean by removing the ‘FX’ do you mean you don’t want the Arduboy FX to start with the menu and just start the last flashed game?

If this is the case and you have the fx mod chip installed. You can use the FX activator to reflash the bootloader with the ‘power up with game’ option selected.

If you have the Arduboy FX you’ll have to reflash the bootloader manually using an ISP programmer like an USBasp or an Arduino programmed as ISP.

The stock bootloader can be flashed from the Arduino IDE. Just select Arduino Leonardo as board and use the burn bootloader option. You still need an ISP programmer for this. You can select the programmer type from the tools menu as well.

It is not recommended to reflash the stock bootloader. Some games make it hard to upload a new game to Arduboy. It is recommended to burn ‘Cathy3K starts with game’ instead. You can choose this bootloader when the Arduino Homemade package is installed.


Or … ask around. I am sure someone would swap their old Arduboy for an FX.

Not sure where you are located, but I would do that myself.

The Arduboy FX still functions like a normal Arduboy, in that you can still upload and play a normal game you upload via arduino. You get the menu but you press a button and it takes you into the previously loaded game.

As @mr.blinky mentioned it requires an external programmer to change the bootloader to a normal Arudino bootloader.



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Thank you for your replies.
I wish to remove the FX modchip (flex pcb) and give to a friend (We don’t want to swap each others’ Arduboys).

Once I desolder the modchip, I want my Arduboy FX to function as a regular a regular Arduboy.

I understand about the ISP programming.
The help that I need from you fine folks is what do I burn back on the Arduboy to make sure it works after the modchip is taken away.

Does the fx chip work? If so, why not leave it??

Because I will be removing the W25Q128 chip and the flex PCB.
That is something I wish to do.

Once I do this, the Arduboy FX will no longer be able to see the flash storage.

I just want to work as regular Arduboy after that, without the FX bootloader.

Can you guide as to what I need to burn on the Arduboy FX to make it work like a regular Arduboy after that?

The FX bootloader is not exclusively for the FX it is a replacement bootloader for Arduboy as well. It doesn’t depend on the flash storage.

I suggest you upload the FX activator sketch to your Arduboy with modchip and choose the powerup with game as mentioned before. Your Arduboy will function as normally but the advantages are that when you have a upload problem you can simple press the down button while turning power on to enter bootloader mode instead of pressing the tiny reset button and when your Arduboy is in bootloader mode you will see a USB boot icon to confirm the Arduboy is in bootloader mode instead of a black screen.

The choice is yours ofcourse. When you want the genuine Arduboy experience including the upload issues then feel free to upload the stock bootloader. Checkout this thread on how to do it.

To desolder the flex PCB you can heat the solderjoints one at a time from the outside in and slide a piece of paper between the Arduboys PCB and flex PCB. After you’ve removed the flex PCB check the solderpads for any stray solder that may cause shorts.

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Thank you for your precise instructions.

I removed the flex pcb (and by extension, removed memory chip).
I burnt your bootloader Cathy3K (starts with game) using Arduino as ISP.
All this went smoothly.

Next, I tried to upload the simple programs that come as examples on Arduboy - helloworld, buttons, etc.
They all work fine.
However, LeWord does not. Screen simply stays blank.
The USB logo comes when I hold the button when doing startup. So I can verify that the bootloader was flashed correctly.

Ok…So you…removed the FX capability from your arduboy…to play an FX only game…Am I reading this correctly.

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Same behavior with other non FX only games, as well

Also, not related to the above flashing, but can someone help me debug this:

Photo 18-03-22, 8 50 36 PM

It was working fine and suddenly it’s all warped now.

In bootloder, the usb icon is properly center aligned.

Since the examples work all seems fine. I’d say it’s with the games you’ve tried.
What are those other games? did you upload them through the IDE? what settings did you use? did you upload hexfiles? if so from where?

It’s hard to help with so little context.

Can you give more context? is that a screenshot of 8BitCADE XL Level UP? if so make sure you’ve selected the correct board and settings in the Arduino IDE.

Understood your point about games. Will see what I am doing wrong since examples did work correctly.

Unrelated to the “FX” flashing above, I do have the screen issue on the 8bitcade level up.

Uploading through IDE and using the following settings:

I also tried these, but they also result in same problem:

Both the above settings upload the code fine and work also well.
Just that the screen is warped.

The first screenshot has the wrong settings (board should be Pro Micro Alternate) the 2nd is good. If there are no changes I wonder if you have installed any libraries manually. When you have they will override the Homemade package libraries. You need to remove them.

No libraries have been installed manually.

All have been installed using library manager.

That’s what I ment. you need to remove them

This is like wanting to buy a ferrari but replace the engine with a toyota.

Why am I getting so much grief here?
I’m just trying to do things my way and learning a bunch in the process.
Sorry if I am taking too much of your time, I won’t ask anymore on this.
Thank you @Mr.Blinky, your help was invaluable.

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We worked on this feature for like 4 years and you want to take it out. It’s honestly confusing to me why you would want to remove features. We make a mod chip that is designed to upgrade the origonal device, I never would have thought for a moment that someone wouldn’t want it so it’s something I’m trying to understand.

For the record, it’s totally fine and if you want to modify your device you’re more than welcome to do it. More power to you. I can see the reason maybe to want the original bootloader back to do some development related to it, or you really don’t like the bootloader menu.

Sorry to make you feel uncomfortable, it was intended as just some friendly ribbing.

Have you considered buying an original Arduboy? You can probably still find them from a distributor somewhere and certainly used on ebay.

On a completely practical note, it’s not recommended to remove the serial flash chip. You’ll have to remove the snap dome button matrix sticker to avoid damaging it with hot air. You will find that the button sticker will deform and the adhesive is not designed to be re-applied so you will get bubbles underneath the sticker and could potentially have problems with the buttons later on.

Also, be sure to keep the heat away from the OLED as it has a polarizer film on the top layer that can also be easily damaged by heat. Covering it with some polyamide tape or even some aluminum foil can help with that.

Shine on you crazy diamond.