Hi there,
an op1 patch file consists of two parts: hidden data storing the configuration + a short audio preview. On a computer you can only hear the preview. But if you transmit the patch to the op1, it will only deal with the hidden data.
If you created a patch with an old firmware versions of the op1 and transmit it to a computer, the preview would only say “op1 patch”. This is probably how Cuckoo’s patches were created.
For newer firmware versions this behavior changed. Synth patches from the op1 now contain a “correct” preview. This is at least true for patches stored at the 8 user presets. I heard (but did not verify) that this is now also the case for the other synth patches.
This implies you can add a preview to op1 patches if you copy them to your op1, restart it, and then copy them back. A while ago, I wrote a linux script which can do this for you automatically see here.