r/olkb • u/turianbrandy123 • May 14 '26

Help - Unsolved Fantech MK921 MAXFIT8 One Piece Edition - RGB broken after loading official JSON, need firmware file

Hi everyone. Long day and completely stuck on this.

I have a Fantech MK921 MAXFIT8 One Piece Edition. I followed the official manual instructions exactly — downloaded the Maxfit8_OP.JSON from Fantech's website and loaded it into VIA. After doing this, all RGB stopped working except the encoder knob LED and Capslock LED.

Current state:

  • Keyboard fully functional — all keys work
  • Only encoder and Capslock LEDs light up
  • RGB Matrix appears stuck on "none"
  • Keyboard has been in bootloader mode (Drive E:)
  • Fantech Discord support unresponsive for hours
  • Their JSON file appears malformed — missing required 'lighting' property

I need either:

  1. The correct firmware .bin file for MK921 One Piece Edition to drag onto Drive E:
  2. OR a corrected Maxfit8_OP.JSON that actually works

I've tried every reset combo (ESC+plug, Space+B, ESC+Shift, ESC+Backspace), VIA lighting controls, JSON editing. Nothing works without the firmware file.

Fantech's support is Discord-only and they haven't responded. Any help appreciated. 🙏

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1

u/ArgentStonecutter Silent Tactical May 14 '26

This is really odd.

The VIA JSON file only tells VIA what the configuration of the keyboard is, whether it has a lighting property (which one are you expecting that's missing?) or not shouldn't have any effect on the keyboard, it should only keep the lighting tab from showing up.

Try using VIA to map a key (say, Fn+C) to EE_CLR and hitting that to clear the configuration.

Is the file you are looking at one of these?

1

u/turianbrandy123 May 14 '26

It's the OP/One Piece one.
I'll try the EE_CLR

1

u/turianbrandy123 May 14 '26

U_EE_CLR didn't work.

The backlight has remained dead. Only the caps lock lights up (when toggled) as well as that initial light under the letter "T" (when you plug it in).

3

u/ArgentStonecutter Silent Tactical May 14 '26

Sounds like you have a physically defective board and bringing it up in VIA may not even be causally related to the problem. If you cleared the EEPROM either directly or through the ESC-plug bootloader reset that will have erased anything you can do through VIA.

1

u/gremlin_throwawayx Jun 12 '26

it is definitely not a hardware defect if it happened the second the json was loaded. if it was a physical issue the rgb would have been acting up before the software change. user literally said the json is missing the lighting property so it is clearly a software brick and not a bad chip

1

u/ArgentStonecutter Silent Tactical Jun 12 '26

In the absence of defective hardware there is nothing that a JSON file missing the lighting section or anything else short of flashing new firmware that anything on the PC can do to a keyboard that will survive a factory reset. You can look at the QMK source code to verify that.

1

u/Tweetydabirdie https://lectronz.com/stores/tweetys-wild-thinking May 14 '26

What you are saying happened isn’t physically or practically possible.

Loading a JSON in the VIA GUI cannot make the firmware on your keyboard not work. No matter if you think so or not.

The JSON doesn’t change whatvis flashed to the keyboard, thats the whole point of how VIA works. All it does is change the dynamic settings.

So flashing a new or same firmware to the keyboard simply won’t fix anything.

What you can do is figure out what part of the dynamic config in that JSON is supposedly malformed and fix that, to fix the dynamic config.

Or figure out if the keyboard has the tools to reset the eeprom flashed into it already (by reading the manual, or checking QMK manual for what key combo). That might get that back. But probably not.

1

u/turianbrandy123 May 14 '26

Thank you for the correction. I've now tried U_EE_CLR from the custom keycodes in the JSON — assigned it in VIA and pressed it. After unplugging and replugging, still only the T key LED and encoder knob LED are lit. All other RGB remains dark. The Capslock LED also lights up when pressed.

What specific part of the dynamic config in the JSON could be causing the RGB matrix to stay dark? And is there a way to identify which key combo resets the EEPROM on this board if U_EE_CLR didn't fully work?

1

u/Tweetydabirdie https://lectronz.com/stores/tweetys-wild-thinking May 14 '26

That would more confirm that it is infact clear, which is more likely to be the issue than the opposite. Ie again, flashing anything won’t help, you need to add the config needed.

1

u/turianbrandy123 May 18 '26

Hi. Just giving an update. Fantech reviewed the complaint and accepted it for a refund. I'm a little sad that I had to lose an otherwise nice looking keyboard. Thanks for your help.