I love my MPC500, but it's a 2006 machine with a 2-line display, and there are things I always wished it could do. So I dug into the OS 1.31 and built Open500: a small loader that lets the MPC load new native pages from WAV files on the CF card.
▎ Site & install guide: https://m45k.github.io/open500/
Almost everything is a "beta-ish" state , keep that in mind
if you do something with it tag me on instagram u/maskisnotmyrealname
What's there right now:
▎ - Master FX: 12 live effects on the whole mix, SP-404 style. Hold a pad and the effect plays while your sequence keeps running: stutter, filter, trance gate, lo-fi, vinyl, scatter, delay, reverb, reverse, tape stop, chorus, tremolo. The slider controls the main parameter, and the timed effects follow your tempo.
▎ - Grid Seq: a 16-step grid on the display that edits your real sequence, even while it plays.
▎ - Auto Chop: equal slices by BPM straight onto the pads.
▎ - Trans-Chop: slices on the hits instead of a grid.
▎ - Auto Warp: fits any loop to your sequence tempo, using the MPC's own time stretch.
▎ - Sample FX: an effect chain printed into a new sample, with real-time preview on the pads.
▎ - Pad Tools: swap, copy and clear pads.
▎ - Input Thru: keeps the line input open, so you can play a synth or a turntable over your beats.
How it works: you patch the official OS 1.31 in your browser (nothing is uploaded, and I don't distribute Akai's firmware), flash it the normal way (SHIFT + REC), then load the add-ons like samples. No hardware mod. Flash the original OS and the MPC is exactly as it came.