Builder

Build your update

Choose the official CDJ-900NXS 1.31 update, tick the mods, download your C900NXS.UPD. It all runs in your browser.

The official update

Pioneer DJ's C900NXS.UPD for firmware 1.31. The builder checks its SHA-256 and refuses any other file.

Choose C900NXS.UPD or drop it here No file yet

The mods

Ticking a mod also ticks what it needs; unticking one unticks what needs it.

On: no mods, the official 1.31 relabelled so the player takes it — the way back.

Before you build

Unofficial firmware. Flashing modified firmware can leave your player unusable. The boot loader and the recovery stay untouched, so an official update can still be run, but there is no guarantee.

I flash this at my own risk. The authors accept no liability for any damage to my player, my data or anything else. I understand that our mods, this builder and the website were written with Claude Code (Anthropic's AI coding assistant, Claude Opus 5.5) and tested in an emulator and on one player.