So indeed I can also reproduce this again (immediate crash when offloading data from Nano 33 BLE Sense). So fun! Will investigate today.
edit: My feeling right now (based on the earlier investigation of a similar bug) is that we receive too many events too fast, with some of them potentially overlapping (so a new data frame comes in before the previous one was handled) and there is a mutex somewhere in the Chrome code which gets tripped because of this, leading to the hardfault. We’ve seen this in the past when our buffer handling code in the
data event handler of the Web Serial API was not fast enough. The reason why this happens on the Nano 33 BLE Sense is that it’s using a much higher baud rate than other boards, leading to a lot less tolerance here (and changing between releases as well, as @sergi and I spent a lot of time looking at edge cases around random browser crashes a few months back, and the issue did not occur anymore on all fully supported dev boards). My next try is to see if adding artificial delays on the firmware side could help.
edit 2: Using smaller buffers and adding delays between writes indeed seems to resolve the issue, but at the cost of significant lower transmission speed. I’ve put together a beta build here:
And will work on finalizing and landing a fix for everyone early next week. @Jim_Newcaretec @mjrovai