@seindal @starlabssystems Thanks! Tried it, alas no effect.
Note: I went through the git repo history, and saw that after the last update to ibt-0040-2120.*, four other files related to Jefferson Peak were updated (commit c402d0cd627...), but the driver did not apparently load them. Just in case, I copied them under /lib/firmware/intel, but that had zero effect too.