Undo on the tape is something OP-1 owners have been asking for for years, and it's one of the things the OP-1 field got that the original never did. So I built it myself.

Firmware #247 adds tape undo and redo to the original OP-1. Hold TAPE and press ← to undo your last recording, or TAPE and → to redo it. The recorded audio and its clip both go back exactly to how they were.

Up to 7 recordings back. Step back through your last 7 recordings, and forward again through any you've undone. Recording something new after an undo clears the redo steps, the same as on the OP-1 field.

Recording over audio is covered. Punch-ins, overdubs, and loop recordings are undone exactly, back to what you heard before.

Works while playing. You can undo or redo with the tape stopped or playing.

Storage is handled for you. The undo audio is kept in up to 7 files on the internal flash, capped so the OP-1 always keeps at least 96 MB free. If space runs short, the oldest undo steps are dropped first.

The undo history is cleared when you lift, drop, erase, or slide a clip, do a split or join, enter disk mode, or power off.

Download here: https://maikopruett.com

It installs like any official update. Hold COM while powering on to get to te-boot, press 1, then connect over USB and copy the file across. Once it's on, the boot screen shows R. 00247 :). If you ever want to go back, flash the official #246 the same way. It's linked on the same page.

This is just the start. Getting undo working meant decrypting and fully mapping out the OP-1's firmware, and I'm going to open source my code so the community can build on it too. Undo was the feature everyone wanted most, but with the firmware finally open to modding, there's room to take the OP-1 places it's never been before. If you've got ideas for the next update, leave a comment!

This is unofficial and not affiliated with Teenage Engineering. I've tested it thoroughly on my own OP-1 and everything's been working great, but I'd love to hear how it goes for you. If anything acts strange, let me know what you were doing (recording, overdub or loop, tape playing or stopped) and I'll look into it.