@mythbu thanks a lot for sharing this! I remember my own long nights back in 2018, where @sza2-sza2 and me finally got i2s working (that forum thread you found and linked above ). Sorry that I did not see your original question earlier, only the solution now - if I did, I might have been able to help a bit. Anyway, glad to hear you got it working! But what I don‘t understand: why did the i2s support disappear again after b177? As I‘m using only custom openwrt images, I lost track of details happening in the official onion releases. Since b177, i2s support was a ticked checkbox in my mind…

@Juan-Marcelo-Arteaga-0 Do you have alsautils installed and the right sound card within alsa-mixer selected?

Small update: I followed the track Sven started in November a bit through kernel sources and found that the BUG-ON() statement which causes the crash might be itself a bug, because it blocks a code path that seems legit to me. At least, when I experimentally removed the BUG_ON(), aplay does not crash any more but produces a i2s WS signal for the right duration However, no sound yet - I haven't been able yet to check if this is a problem of my hardware (with very difficult to solder MAX98357A) or still DMA not piping the data to the i2s. I'm also trying to check with the author of that BUG_ON statement to find out why exactly he did put it there.

It seems like Onion only partly discontinued the Rocki expansion. I've gone through Onion's blog. Shipping of the Rocki expansion is still mentioned in the Kickstarter and Indiegogo updates on February 22 and 24 (https://onion.io/blog-kickstarter-update-february-22-2017/). About two weeks later, in the Kickstarter update on March 6, it is listed as no longer available due to manufacturing difficulties. Nothing is said in that particular update about the Rocki expansions that were actually shipped. But in the Kickstarter and Indiegogo updates on march 8, they repeat that it is no longer available. But they also add, "This applies to backers who have not yet completed the survey. If you have already completed your survey and ordered these items, you will be getting them!". And that's the last mentioning of the Rocki expansion in Onion's blog. So, of course I am hoping for some kind of documentation.