Installed FX mod chip, stuck on USB boot screen

Quick background: I ordered on April 2016 a pre-order Arduboy. Once I got it in the summer of 2016, I installed a game on it, played it for a week or so, then got distracted building other retro handheld game emulators ever since. Recently I read a hack-a-day article about the FX mod chip and thought that’s a great idea, let me order one! Found where I left my Arduboy, charged it up and played the game I installed long long ago. Still works great!

The Pre-Programmed FX Mod chip I ordered was super easy to solder in. I followed the directions from Arduboy – Start FX and reset it via the reset button (also tried shorting GND and RST) for 5 seconds. I then waited 30 seconds. All I ever see on the screen now is “USB boot”. During installation, I used kapton tape to lock in the mod chip location to make the soldering easier (been doing SMT soldering for decades now). Just in case, I’ve reflowed the solder connections multiple times with no improvements. Also used a DVM to ensure there were no shorts between the solder connections I made.

Is it possible that I had such an old bootloader installed previously on my Arduboy that the pre-programmed FX mod chip can’t boot?

Any other debugging or troubleshooting tips I should try?

FYI: I’m able to install and run Arduboy2 program examples from Arduino just fine. However, if I power cycle my Arduboy, it goes right back to the “USB boot” screen and stays on that screen forever. No button press makes any difference.

The bootloader will have been correctly updated if you are sing the USB boot logo, so that isn’t the issue. The reason for seeing that icon is if it cannot detect the external flash.

It’s probably worthwhile trying to use the FX Activator to run some diagnostics from the device:

You can upload the hex circled here in green using a variety of the hex uploading tools like erwins or strictly avrdude. Or the included activator tool in python. If you don’t have the python environment setup you can use the portable version within the zip file circled in red:

By running the activator it should tell you what the status is of the Flash.

Try that out and let us know what your results are.

Thanks Kevin! Took awhile to debug issues with pkg and Win10. The dir tree structure did not have files in the right locations. Running the python script with --verbose mode revealed that tcl and tk were not in the expected locations. Example error:
_tkinter.TclError: Can’t find a usable tk.tcl in the following directories

Had to create this dir: .\Arduboy-FX-mod-chip-master\portable-activator\lib and copied into that dir files from .\Arduboy-FX-mod-chip-master\portable-activator\Python\tcl
Once those files were added to the new location, the FX Activator could start on Win10

I uploaded the Hex file and on the Arduboy screen it shows status:
MOD CHIP (check)

Diagnostics show:
L fuse: FF E fuse: CB
H fuse: D2 Lock: FF
BootCRC: D62C v1.9

Is this still a solder issue or do I just need to flash an image at this point?

That’s weird I’ve used that zip file on 3 different win 10 machines without any issues. Do you have python installed otherwise?

Ok, welp, I’ve certainly won The Idiot of the Day prize today…
Not sure how I pulled it off, but I completely missed soldering in the SDA pad, even after I had closely examined the FX mod board multiple times. DOHHHHH!!! Once the I2C serial data pin SDA pad was soldered, everything worked as expected with Portable Activator and booting and game selecting on the Arduboy.

Thank you again Kevin for all of your support! I’ll PM you more details on the Win10 issues I saw with running FX Activator. tl;dr: looks to be a Win10 issue parsing paths incorrectly…


The SDA pad is actually just used as a chip select for the SPI flash. Glad you got it though!

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